Tag: climate change

Why the aviation industry must look beyond carbon to get serious about climate change

Posted on by janet.crompton

 

Flying is responsible for around 5% of human-induced climate change.
Wichudapa/Shutterstock

Commercial aviation has become a cornerstone of our economy and society. It allows us to rapidly transport goods and people across the globe, facilitates over a third of all global trade by value, and supports 87.7 million jobs worldwide. However, the 80-tonne flying machines we see hurtling through our skies at near supersonic speeds also carry some serious environmental baggage.

My team’s recent review paper highlights some promising solutions the aviation industry could put in place now to reduce the harm flying does to our planet. Simply changing the routes we fly could hold the key to drastic reductions in climate impact.

Modern aeroplanes burn kerosene to generate the forward propulsion needed to overcome drag and produce lift. Kerosene is a fossil fuel with excellent energy density, providing lots of energy per kilogram burnt. But when it is burnt, harmful chemicals are released: mainly carbon dioxide (CO₂), nitrogen oxides (NOₓ), water vapour and particulate matter (tiny particles of soot, dirt and liquids).

Aviation is widely known for its carbon footprint, with the industry contributing 2.5% to the global CO₂ burden. While some may argue that this pales in comparison with other sectors, carbon is only responsible for a third of aviation’s full climate impact. Non-CO₂ emissions (mainly NOₓ and ice trails made from aircraft water vapour) make up the remaining two-thirds.

Taking all aircraft emissions into account, flying is responsible for around 5% of human-induced climate change. Given that 89% of the population has never flown, passenger demand is doubling every 20 years, and other sectors are decarbonising much faster, this number is predicted to skyrocket.

Aircraft contrails don’t last long but have a huge impact.
Daniel Ciucci/Unsplash

It’s not just carbon

Aircraft spend most of their time flying at cruise altitude (33,000 to 42,000 ft) where the air is thin, to minimise drag.

At these altitudes, aircraft NOₓ reacts with chemicals in the atmosphere to produce ozone and destroy methane, two very potent greenhouse gases. This aviation-induced ozone is not to be confused with the natural ozone layer, which occurs much higher up and protects the Earth from harmful UV rays. Unfortunately, aircraft NOₓ emissions cause more warming due to ozone production than they do cooling due to methane reduction. This leads to a net warming effect that makes up 16% of aviation’s total climate impact.

Also, when temperatures dip below -40℃ and the air is humid, aircraft water vapour condenses on particles in the exhaust and freezes. This forms an ice cloud known as a contrail. Contrails may be made of ice, but they warm the climate as they trap heat emitted from the Earth’s surface. Despite only lasting a few hours, contrails are responsible for 51% of the aviation industry’s climate warming. This means they warm the planet more than all aircraft carbon emissions that have accumulated since the dawn of powered flight.

Unlike carbon, non-CO₂ emissions cause warming through interactions with the surrounding air. Their climate impact changes depending on atmospheric conditions at the time and location of release.

Cutting non-CO₂ climate impact

Two of the most promising short-term options are climate-optimal routing and formation flight.

Left: Climate optimal routing. Right: Formation flight concept.

Climate-optimal routing involves re-routing aircraft to avoid regions of the atmosphere that are particularly climate-sensitive – for example, where particularly humid air causes long-lived and damaging contrails to form. Research shows that for a small increase in flight distance (usually no more than 1-2% of the journey), the net climate impact of a flight can be reduced by around 20%.

Flight operators can also reduce the impact of their aircraft by flying in formation, with one aircraft flying 1-2 km behind the other. The follower aircraft “surfs” the lead aircraft’s wake, leading to a 5% reduction in both CO₂ and other harmful emissions.

But flying in formation can reduce non-CO₂ warming too. When aircraft exhaust plumes overlap, the emissions within them accumulate. When NOₓ reaches a certain concentration, the rate of ozone production decreases and the warming effect slows.

And when contrails form, they grow by absorbing the surrounding water vapour. In formation flight, the aircraft’s contrails compete for water vapour, making them smaller. Summing all three reductions, formation flight could slash climate impact by up to 24%.

Decarbonising aviation will take time

The aviation industry has fixated on tackling carbon emissions. However, current plans for the industry to reach net zero by 2050 rely on an ambitious 3,000-4,000 times increase in sustainable aviation fuel (SAF) production, problematic carbon offsetting schemes, and the introduction of hydrogen- and electric-powered aircraft. All of these could take several decades to make a difference, so it’s crucial the industry cuts its environmental footprint in the meantime.

Climate-optimal routing and formation flight are two key examples of how we could make change happen faster, compared with a purely carbon-focused approach. But there is currently no political or financial incentive to change tack. It is time governments and the aviation industry start listening to the science, and take aircraft non-CO₂ emissions seriously.The Conversation

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This blog is written by Cabot Institute for the Environment member Kieran Tait, PhD Candidate in Aerospace Engineering, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Kieran Tait

 

 

Arctic is warming nearly four times faster than the rest of the world – new research

Posted on by janet.crompton
New research estimates that the Arctic may be warming four times faster than the rest of the world.
Netta Arobas/Shutterstock

The Earth is approximately 1.1℃ warmer than it was at the start of the industrial revolution. That warming has not been uniform, with some regions warming at a far greater pace. One such region is the Arctic.

A new study shows that the Arctic has warmed nearly four times faster than the rest of the world over the past 43 years. This means the Arctic is on average around 3℃ warmer than it was in 1980.

This is alarming, because the Arctic contains sensitive and delicately balanced climate components that, if pushed too hard, will respond with global consequences.

Why is the Arctic warming so much faster?

A large part of the explanation relates to sea ice. This is a thin layer (typically one metre to five metres thick) of sea water that freezes in winter and partially melts in the summer.

The sea ice is covered in a bright layer of snow which reflects around 85% of incoming solar radiation back out to space. The opposite occurs in the open ocean. As the darkest natural surface on the planet, the ocean absorbs 90% of solar radiation.

When covered with sea ice, the Arctic Ocean acts like a large reflective blanket, reducing the absorption of solar radiation. As the sea ice melts, absorption rates increase, resulting in a positive feedback loop where the rapid pace of ocean warming further amplifies sea ice melt, contributing to even faster ocean warming.

This feedback loop is largely responsible for what is known as Arctic amplification, and is the explanation for why the Arctic is warming so much more than the rest of the planet.

Blocks of melting sea ice revealing a deep blue sea.
Melting sea ice in the Arctic Ocean.
Nightman1965/Shutterstock

Is Arctic amplification underestimated?

Numerical climate models have been used to quantify the magnitude of Arctic amplification. They typically estimate the amplification ratio to be about 2.5, meaning the Arctic is warming 2.5 times faster than the global average. Based on the observational record of surface temperatures over the last 43 years, the new study estimates the Arctic amplification rate to be about four.

Rarely do the climate models obtain values as high that. This suggests the models may not fully capture the complete feedback loops responsible for Arctic amplification and may, as a consequence, underestimate future Arctic warming and the potential consequences that accompany that.

How concerned should we be?

Besides sea ice, the Arctic contains other climate components that are extremely sensitive to warming. If pushed too hard, they will also have global consequences.

One of those elements is permafrost, a (now not so) permanently frozen layer of the Earth’s surface. As temperatures rise across the Arctic, the active layer, the topmost layer of soil that thaws each summer, deepens. This, in turn, increases biological activity in the active layer resulting in the release of carbon into the atmosphere.

Arctic permafrost contains enough carbon to raise global mean temperatures by more than 3℃. Should permafrost thawing accelerate, there is the potential for a runaway positive feedback process, often referred to as the permafrost carbon time bomb. The release of previously stored carbon dioxide and methane will contribute to further Arctic warming, subsequently accelerating future permafrost thaw.

A second Arctic component vulnerable to temperature rise is the Greenland ice sheet. As the largest ice mass in the northern hemisphere, it contains enough frozen ice to raise global sea levels by 7.4 metres if melted completely.

A man and woman standing on the edge of a flooded coastal road.
The Greenland ice sheet contains enough frozen ice to raise global sea levels by 7.4 metres if completely melted.
MainlanderNZ/Shutterstock

When the amount of melting at the surface of an ice cap exceeds the rate of winter snow accumulation, it will lose mass faster than it gains any. When this threshold is exceeded, its surface lowers. This will quicken the pace of melting, because temperatures are higher at lower elevations.

This feedback loop is often called the small ice cap instability. Prior research puts the required temperature rise around Greenland for this threshold to be be passed at around 4.5℃ above pre-industrial levels. Given the exceptional pace of Arctic warming, passing this critical threshold is rapidly becoming likely.

Although there are some regional differences in the magnitude of Arctic amplification, the observed pace of Arctic warming is far higher than the models implied. This brings us perilously close to key climate thresholds that if passed will have global consequences. As anyone who works on these problems knows, what happens in the Arctic doesn’t stay in the Arctic.The Conversation

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This blog is written by Cabot Institute for the Environment member, Jonathan Bamber, Professor of Physical Geography, University of Bristol.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

IPCC blog series – Working Group 3 – Mitigation of climate change

Posted on by janet.crompton

This blog is part of a series on the Intergovernmental Panel on Climate Change’s recent 6th Assessment Report, with this post covering the output of Working Group III and the proposed solutions and mitigations for the climate crisis. This article also features a chat with IPCC Lead Author Dr Jo House and contributor Viola Heinrich, researchers at the University of Bristol and Cabot Institute for the Environment. 

Of the three Working Groups, the third makes for the most positive reading. As the title suggests, this one is all about the mitigation of climate change and preventing the disastrous climate futures explained by Working Groups I and II. Whilst remaining focussed on the impending nature of the climate crisis, this report spells out that we have the solutions.

As discussed in the previous posts, massive behavioural changes are needed at government and societal levels. When I spoke to academics, they were positive that we were well past the point of whether climate change is real or has an impact on humanity and that economically minded leaders are starting to see the benefits of sustainable practice and the economic security it brings. Governments and states are listening and looking at policy to mitigate the crisis.

Let’s look at some of the solutions and mitigations proposed:

The quicker we act, the less economic impact

This follows on nicely from previous reports that stated the effects of warming increase with each incremental global average temperature increase. That is to say, a +1.5 degrees C future will see less devastation than a +2 degrees C or even a +1.7 degrees C rise in temperature. Such disasters (drought, extreme weather, flooding) require huge amounts of money resources to sort out. From an economic security point of view, it makes complete sense to act with great urgency. The climate crisis is already here, and therefore already having an economic impact. Action immediately will mitigate against the future potential costs of a climate disaster.

Relative to the economic impact of climate disaster in the future, the investment of reducing the impact of the crisis and securing a liveable planet is small.

The immediate reduction of fossil fuel production and limitation of greenhouse gases in the pursuit of Net Zero

As discussed before, the greatest culprit of the climate crisis is unequivocally greenhouse gas (GHG) emissions from fossil fuels. Therefore, in an ideal world, the immediate halt of fossil fuel extraction, production and consumption would be enough to prevent an overshoot +1.5 degrees C (as discussed in the first report, there is a lag between emissions and warming). Unfortunately, this is not an ideal world, so significant policy to pursue a Net-Zero will be needed.

Going further, carbon must also be removed from the atmosphere somehow, to allow the planet to return to preindustrial atmospheric carbon levels.

Carbon removal, naturally and technologically

A key aspect to the third Working Group is its arguments for carbon capture. This could be either through natural carbon removal through plants and trees, or by using carbon removal technology through direct air capture.

Carbon capture will be essential to solving the climate crisis, as carbon needs to be removed in order to return to the pre-industrial levels of atmospheric carbon. As well as this, proposed tech allows for carbon to be captured at the source of emissions. The issue is that carbon capture could lead to a dependence on the technology.

Companies, understandably, are drawn to the idea of “planting trees” to offset their emissions. It’s visible, tangible, and easy for the public to grasp. However, it’s not always the most efficient use of land and resources, and some worry that these methods will be exploited as a crutch to not reduce emissions output. While an extremely important step in mitigating climate change, some worry that there may be a resultant reliance on carbon removal over carbon emission reduction, allowing the world’s most prolific polluters to continue maintain their carbon output.

One of the most cost-effective mitigation techniques is simply the protection of existing forests and natural sites. The IPCC also stresses that decisions of protection like these must involve the input of the indigenous communities living there.

From the policy level to the personal level

It’s brilliant to be making the personal decisions to limit your own carbon impact, but individuals have limited impact on the climate system. What these reports suggest is wide reaching policy at state level to incentivise populations to make better climate conscious choices, by making things easier through improved infrastructure and methods of “demand management”, reducing the consumption of resource intensive products like meat and dairy. Diet changes at a population scale will be needed to combat the emissions of methane (another greenhouse gas) in particular.

In urban environments, investment in public transportation and cycling infrastructure would go a long way to reduce emissions. As would policy that makes retrofitting buildings to be more energy efficient and building new infrastructure with energy efficiency in mind.

For a great bit of further reading, the IPCC Special report on Climate Change and Land goes into much further detail about the impact of changing diets and consumption habits at scale.

Read the IPCC Special Report on Climate Change and Land

As previously discussed in the blog post on the WGII report, the impacts of climate change are not equal or in proportion to climate impact of the nation affected. Therefore, much of the mitigation will need to take the form of humanitarian aid, improving infrastructure for nations without the resources to do so themselves.

The IPCC reports end on a poignant note: “International cooperation is a critical enabler for achieving ambitious climate change mitigation goals”.

Insight from IPCC Lead Author Dr Jo House and contributor Viola Heinrich

Dr Jo House

Dr Jo House is Reader in Environmental Science and Policy, Research Lead of Cabot Institute for the Environment’s Environmental Change theme and a Lead Author on the IPCC’s AR6 Working Group III report.

Viola Heinrich is a Physical Geography PhD Candidate at the University of Bristol, studying the emissions and climate mitigation potential within the land use sector in the tropics, especially the Brazilian Amazon. Viola assisted Dr House in her AR6 work, producing figures for WG III.

How did you get involved with the IPCC and WGIII?

Dr Jo House – “I have been working on IPCC reports for 20 years. I was first employed as a chapter scientist to support the chapter team for working group I, 3rd assessment report carbon cycle chapter. I was then made a lead author for the synthesis report for AR3. Since then, I have been a lead author or contributing author on all three Working Groups, as well a lead author for the Special Report on Climate Change and Land. I am also a lead author twice for the IPCC Task Force on Inventories, who provide methodological guidance to countries on how to produce their greenhouse gas inventories, for reporting to the UNFCCC, as well as accounting under the Kyoto Protocol.

Viola Heinrich

Despite the long hours and the many thousands of comments we must respond to, I do IPCC because I care about climate change, and IPCC gets the science into the hands of people who can do something about it.”

Viola Heinrich – “I’m a PhD student working on understanding the emissions and climate mitigation potential within the land use sector in the tropics, especially the Brazilian Amazon. Jo, as my supervisor, approached me in 2019 to help produce some figures for her work on AR6 and WGIII.

It was a great learning experience seeing how these report cycles work and one bonus was that the work I produced for the IPCC reports was able used in the introduction to my PhD thesis”

What’s one key message you’d like to highlight from WGIII?

Dr Jo House – “We are nearly already too late to stay within 2 degrees, so we need to reduce fossil fuels usage drastically and rapidly to avoid even worse impacts.

Also specifically from a land perspective: The land has potential for mitigation, but it cannot do it all, planting trees is not a get out of jail free card for continuing to burn fossil fuels.”

Viola Heinrich – “This report has followed nicely on form previous cycles in that it has reaffirmed what we know about the land use component and the mitigation potential of the land use sector (20% to 30% by 2050). The big caveat of course is that the land can’t do it all and we need to be actively reducing emissions rather than relying in capture methods from trees for example.

Another interesting factor about the report is that it stresses the importance of considering the local communities in places where solutions and mitigations take place, seeking their expertise in protection, and understanding how these actions will affect them.”

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As always, we recommend taking a look at the IPCC’s full reports and report summaries for yourself if you seek to further understand the evidence and reasoning behind their headline statements.

That wraps up the blog series, I hope that it was enjoyable and informative.

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This blog series was written by Cabot Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institute’s Master’s by Research in Global Environmental Challenges at the University of Bristol.

Andy Lyford

 

 

IPCC blog series – Working Group 2 – Impacts, Adaptation and Vulnerability

Posted on by janet.crompton

 

 

This blog is part of a series from the Cabot Institute for the Environment on the Intergovernmental Panel on Climate Change’s recent sixth Assessment report, with this post covering the output of Working Group 2 and the impacts of climate change on society and ecosystems. This article also features a chat with Prof Daniela Schmidt, a Professor at the School of Earth Sciences at the University of Bristol, and a Lead Author on the IPCC’s AR6 report. For links to the rest of the series, see the bottom of the post.

Welcome to the next post in this series on the IPCC sixth Assessment Report (AR6). Now that we’ve covered the background science to climate change, the next phase looks at the impacts on society, ecosystems, and the intricate fabric of everything in between – combining the science and aiding the transition of translating to policies that governments can implement to better the planet and mitigate the impacts.

This report is, in my opinion, the most alarming of the bunch – some scientists referring to this as the “bleakest warning yet”. Here are the key points:

The increased frequency of Extreme Weather and Temperature will have a cataclysmic impact – Everywhere will be affected

There is no inhabited region on earth that escapes the impacts of climate change. It’s estimated that over 3.3 billion people are living in areas highly vulnerable to climate change effects – largely extreme temperatures, leading to food insecurity and water shortages. Extreme weather events, such as tropical storms and flooding, are also set to increase in both frequency and severity.

As we’ve seen in recent years, wildfires have become more common (Australia and California making international news) and will continue to rise in frequency – wreaking devastation on communities and wildlife. This, along with the retreat of glaciers and polar ice caps, also results in a release of even more carbon to the atmosphere as the Earth’s natural carbon sinks continue to be dismantled. The ensuing feedback loop amplifies the warming, only serving to increase the severity of these events.

However, the impacts of climate change won’t be experienced uniformly across the planet…

The Impacts of Climate Change will not be experienced equally

This is one of the most important statements from all three Working Groups. It’s been well reported that sea level rise will be existentially cataclysmic for atoll island nations such as Kiribati and the Maldives, but there are other effects of climate change that will be unequally experienced. At the other end of the scale, Britain and other western European nations will see less drastic impacts, despite having some of the greatest contribution to the emissions at the root of the climate crisis. In summer, some parts of the globe are already becoming unliveable due to the extremely high temperatures. In India and Africa for example, where temperatures can exceed 40 degrees C, the number of deaths due to heat are increasing year on year. Poorer communities, especially those who work outdoors, are disproportionately affected as their occupation puts them at greater risk.

Some of the nations with the lowest development and therefore lowest contribution to climate change will experience the impacts more than some of the greatest contributors.

A Climate Crisis exacerbates other ongoing Crises

The effects of a climate crisis add an extra layer of complexity to all sorts of problems the world is already facing. Threats to food and water security because of climate change will increase pre-existing geopolitical tensions as resources become more and more scarce. Therefore, the likelihood of conflict and war increases – which in turn shift focus from fighting climate change. To some extent, we are seeing this already with the war in Ukraine, for example. In summary, climate change can increase severity of a crisis and limits the efficacy of response.

Impacts on ecosystems are already happening as well

Mass die-offs of species are well underway, particularly in oceanic ecosystems as sea temperatures rise and ocean acidification takes place. Deforestation and wildfires are destroying ecosystems.

When I spoke to Professor Daniela Schmidt, a lead author on the WGII report (more from her at the end of the article), she was quick to point out and stress the connections between nature and society, links often underestimated – “Negative impacts on nature will negatively impact people”. Nature, land-use, and conservation will be some of the key tools in helping mitigate the effects of climate change.

This is something to explore further with the next blog in this series on Working Group 3: Mitigation of Climate Change.

Insight from IPCC AR6 Lead Author Professor Daniela Schmidt 

Daniela Schmidt is a Professor of Palaeobiology, Cabot Institute member and a key author on the IPCC’s WG2 report.

How did you get involved with IPCC AR6 and Working Group II in particular?

“I was a lead author on the fifth assessment report, working on the ocean chapter. I have since worked on reports for the European Commission on food from the ocean. I volunteered for this cycle with the expectation of working with WGI but I was assigned work on WGII, which was challenging because it was way out of my comfort zone. Working on this report has changed the way I will conduct research in the future, and has taught me to be more open to the complexities of life”

What’s one key point you’d like to get across from the WGII report?

“The official key strapline from AR6 is that the evidence is clear, climate change is real and happening right now. It’s a rapidly closing window of opportunity to do something about it.”

“One of the main things I like to communicate is that if we don’t hit 1.5 degrees C targets, then 1.7 degrees C is still better than for 2 degrees C example. The point is that every increment matters and that we can’t give up if we miss targets. I think it’s important to tell people that if we are overshooting 1.5 degrees C, yes, there will be consequences, some of which are irreversible, but we can still come back.”

“I also try not just to talk about climate change. Much of the adaptation action for climate change incidentally will, in my view, help to make the world a better place – providing clean drinking water, clean energy, habitable homes and ensuring there is nature surrounding them”

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We recommend taking a look at the IPCC’s full reports and report summaries for yourself if you seek to further understand the evidence and reasoning behind their headline statements.

Going further, potential solutions and climate change mitigations will be covered in greater detail in our summary of WG3’s report titled “Mitigation of Climate Change”, will be the next blog in this series, featuring a chat with IPCC AR6 Lead Author Dr. Jo House and contributor Viola Heinrich.

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Andy Lyford

This blog was written by Cabot Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institute Master’s by Research in Global Environmental Challenges at the University of Bristol.

IPCC blog series: Working Group 1 – The Physical Science Basis

Posted on by janet.crompton

This blog is part of a series from the Cabot Institute for the Environment on the Intergovernmental Panel on Climate Change’s recent AR6 report (IPCC, AR6), with this post covering the output of Working Group 1 and the physical scientific basis of climate change. This article also features a chat with Professor Dan Lunt, a Climate Scientist at the University of Bristol who focusses on paleoclimates and climate modelling, and a Lead Author on the IPCC’s AR6 report. For links to the rest of the series, see the bottom of the post.

The IPCC begins their 6th Assessment Report by explaining the physical science basis and publishing the finding of Working Group 1 (WG1) in August 2021. This means that, rather than considering the impact on humans, ecosystems and societies covered by later working groups, this report only looks at the effects on the planet from a physical standpoint. Consider this part of the report to be describing the problem, where later reports describe the impacts and then the possible solutions.

Here are the key points from WG1, detailing the physical science basis:

Human activity has unequivocally caused a change in the global climate.

If you were in any doubt before, let this be the sole key message you take away from this report.

Human activity has caused widespread warming of the land, ocean an atmosphere, affecting weather systems, ecosystems, and the cryosphere (areas covered by ice such as mountain glaciers and the polar regions).

One of the main drivers of this change has been Greenhouse Gases (GHGs), which have been observed to be increasing in atmospheric concentration since as far back as 1750 and the beginning. These gases, such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), come from human processes that burn fossil fuels – transport, energy production, intense cattle farming for example.

Greenhouse gases in the atmosphere act like blanket, trapping rather than heart from the sun, warming the Earth. We also know from studying past climates that the Earth will get warmer with greater atmospheric CO2 levels.

Changes to the climate are happening at an unprecedented rate.

Figure 1: Graph from AR6-WG1 showing the unprecedented levels of warming seen in the last 2000 years.

You may have heard that the Earth’s climate has naturally ebbed between periods of hot and cold. This is completely true, however it can be a misleading statement that completely undersells the issue. Human activity has caused the planet to warm at an unprecedented rate. We are currently undergoing thousands of years of warming in just a few decades (fig.1) – much to fast for adaptation from the world’s ecosystems.

As such, the Earth will take millions of years to recover and reach an equilibrium. I highly encourage you to check out climatearchive.org’s simulations of the next million years using cutting edge modelling data – created by the Cabot Institute for the Environment’s Sebastian Steinig.

Climate change is ALREADY affecting every inhabited region on Earth, with observed increases in extreme weather and climate extremes.

Many people believe that the climate crisis is far off in the future, a problem to prevent before it arrives. However, this is not the case. It’s already happening under our noses. And everywhere. Every inhabited region in the world currently experiences an increased likelihood of an extreme weather event, extreme heat drought, or extreme precipitation. This summer for example, temperatures in the UK have been modelled and subsequently measured to creep above 40°C, unprecedented for a region with a usually temperate climate and setting national records.

Increased warming leads to an increase in effect and creeps towards a tipping point from which recovery is impossible.

You might have heard phrases like “2 degree C future” or “1.5 degree C rise” in the news, but what do these really mean? These numbers refer to the global mean temperature rise using a rolling average of the previous 20 years, relative to the temperature measured between 1850-1900 when climate change started to begin. Currently, the average global temperature anomaly sits above 1 degree C of warming (fig.1).

The Earth system is remarkably robust, but not quite robust enough to maintain an equilibrium with such rapid warming in a short space of time. One place where this is most stark is the cryosphere – parts of the Earth usually covered by ice all year round (glaciers, polar regions for example).

Melting has already begun and will continue to happen for decades even if emissions magically ended tomorrow. This is incredibly troubling, since the cryosphere also happens to be huge carbon store in the form of methane trapped in the ice. This creates what’s known as a feedback loop, where the effects of warming lead to greater warming in themselves.

Through studying paleoclimates, the IPCC reports that climate sensitivity and therefore “tipping point” sits at around 3 degree C, resulting in total climate breakdown.

Significant and immediate action limiting Greenhouse Gas emissions will be a major key in fighting climate change.

The one silver lining the report alludes to is that IPCC scientists are confident that the climate crisis is caused primarily by greenhouse gas concentrations, therefore we know the solution – reducing emissions quickly and effectively will mitigate against the worst warming in a big way. Pursuing a net-zero CO2 strategy and limiting other GHG emissions will be absolutely necessary. Working Group 3’s report on the Mitigation of Climate Change goes into greater detail on how governments can work together to go about this. This will be published on 29 August 2022.

Insight from IPCC WG1 author Professor Dan Lunt

Professor Dan Lunt is a Professor of Climate Science, Cabot Institute member and a key author on the IPCC’s WGI report.

How did you get involved with IPCC AR6?

Dan Lunt

“I was involved with the previous IPCC report, AR5, providing some data and graphs for a section on polar amplification in past and future climates (the disproportionate warming of the polar regions relative to the rest of the Earth system). This time round, a call went out around four or five years ago for authors to work on the upcoming Sixth Assessment Report. I applied for and was chosen to be a Lead Author on Chapter 7 of the AR6 report – a section focussed the Earth’s radiation budget and Climate Sensitivity, as well as on paleoclimates as evidence for the patterns of global warming, such as polar amplification.”

What’s one key point you’d like to get across from the work of Working Group 1?

“For me, what I would interpret as the key message would be climate change is already happening, and it’s happening all over the globe. It’s unprecedented in terms of its magnitude and its speed of change, relative to the past tens of thousands of years. It’s unequivocally caused by human activity.”

“One of the new key points in this assessment report is that there’s a lot more evidence now that there are changes in the frequency of extreme events. We now have enough data to say that this increased frequency is human induced. So that’s more droughts, floods, extreme heat events etc.”

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We recommend taking a look at the IPCC’s full reports and report summaries for yourself if you seek to further understand the evidence and reasoning behind their headline statements.

As we’ve discussed the scientific basis for climate change, you may be wondering what the real-world impacts. The specific impacts on ecosystems, global health and on human society will be covered in greater detail in our summary of WG2’s report titled “Impacts, Adaption and Vulnerability”, publishing tomorrow (Thursday, 28th of August).

 

This blog was written by Cabot Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institute Master’s by Research in Global Environmental Challenges at the University of Bristol.

Andy Lyford

 

 

Introducing our IPCC blog series

Posted on by janet.crompton

 

This blog is the first part of a series from the Cabot Institute for the Environment on the Intergovernmental Panel on Climate Change’s recent Sixth Assessment Report (IPCC AR6). This post is an introduction to the blog series, explaining what we’re aiming to do here and with a glossary of some climate change terms that come up in the later posts. Look out for links to the rest of the series this week.

What is the IPCC?

The IPCC is the Intergovernmental Panel on Climate Change. Formed in 1988 by scientists concerned about the state of the global climate, they’ve been publishing assessment reports on the climate to advise policymakers and governments to act. This year they published their 6th assessment report (AR6), which has been described as their ‘starkest warning’ about the dangers of climate change. The report was built up of 3 Working Groups and over 2800 experts representing 105 countries covering different aspects, from the base science to the sociological impacts of a climate crisis. Alongside their assessment reports, the IPCC also publish special reports on key issues to explore them in more detail. These topics have included Land Use, Impact on the Ocean and Cryosphere and further clarifications on the goal of mitigating 1.5°C global warming.

The IPCC are the most trusted climate group worldwide, with their work being used in policy decisions all over the world.

What are the three Working Groups?

Each of the working groups focuses on a different part of the climate story, looking at causes, effects, and solutions.

• Working Group 1: The Physical Science Basis (WGI)

• Working Group 2: Impacts, Adaptation and Vulnerability (WGII)

• Working Group 3: Mitigation of Climate Change (WGIII)

What is this blog series covering?

The full reports are well over 1000 pages each, with many chapters, subchapters, and footnotes to wade through. As previously mentioned, the full report is split into the domains of the working groups.

Each report from the Working Groups is then filtered down into its own Summary for Policy Makers, which is still dense and features a lot of explanation of evidence. This is further broken down into the headline statements that get released to the press. Even at this level, it’s hard for ordinary members of the public to take the time to read all the evidence and digest the key points.

The aim of this campaign is to distil the key points in each Working Group report in a short, easily understood, and shareable blog as a tool for public outreach. As well as this, the campaign will feature voices from across the Cabot Institute for the Environment including IPCC authors from each of the working groups.

It’s a nearly impossible job trying to filter down the output of thousands of experts into a digestible snippet, but hopefully readers will come away more informed about the IPCC reports and the climate crisis than before.

This week, we’ll be sharing my report summaries here on the Cabot Institute for the Environment blog as well as on Twitter and LinkedIn, starting this Wednesday [27 July] on the output of Working Group I: The Physical Science basis. Keep an eye out for it!

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This blog campaign was written by Cabot Institute Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institutes’ Masters by Research in Global Environmental Challenges program at the University of Bristol.

What protections are available to people displaced by climate change?

Posted on by janet.crompton

Climate change will impact all our lives in the coming years and many people will experience extreme events due to climate  change resulting in displacement, both internally and across international borders. This has become the reality for some already within low-lying archipelago islands within the South Pacific, such as Tuvalu and Kiribati. Despite the certainty of increased climate change-related displacement, there is still no specific frameworks which protect those moving for climate related reasons (see a detailed discussion here). 

The site of the village of Tebunginako, Kiribati – relocated due to severe coastal erosion and saltwater intrusion (image: Department of Foreign Affairs and Trade, Australia)

Are people displaced by climate change refugees? 

Under Article 1(A) of the 1951 Refugee Convention, climate-related displacement does not constitute grounds for international protection. I will take the essential elements of Article 1(A) in turn. First, a refugee must have crossed an international border, whereas climate-related displacement is expected to be predominantly internal. 

 

Second, a refugee must have a well-founded fear of persecution. Persecution requires an egregious violation of human rights, which is assessed in light of the nature of the right and the severity of the violation (see here for further discussion). It also requires that the fear of persecution must be well-founded – this does not require certainty – but it must not be far-fetched and should be based upon both an objective assessment of the likelihood of persecution and the subjective nature of the individual’s fear (see Chan v Minister for Immigration and Ethnic Affairs, 1989). Climate change is unlikely to fulfil this requirement despite the detriment it can have on an individual’s access to human rights. It is unlikely to meet the severity threshold even in relation to socio-economic rights and, as McAdam (2016) highlights, it is difficult to identify a ‘persecutor’ that the refugee fears; instead, many refugees are likely to be moving to states that are major greenhouse gas contributors. 

 

Third, persecution must be related to a reason given by the Convention of ‘race, religion, nationality, membership of a particular social group or political opinion…’ The impacts of climate change do not discriminate. Even if an individual did establish persecution based upon an egregious socio-economic rights violation caused by climate change, they would need to argue that this affected them because of their membership of one of these groups. At best, an individual could argue that a government had consciously withheld assistance to address the impacts of climate change to a specific group, amounting to persecution (see here) but the group must be connected by an immutable characteristic (Applicant A v Minister for Immigration and Ethnic Affairs, 1997), not just the impact of the climate change. 

 

Courts have firmly established that the Refugee Convention does not protect victims of natural disasters, slow-onset degradation, poor economic conditions or famine – even when the country of origin is unable or unwilling to provide protection (Canada (Attorney General) v Ward, 1993; Horvath v Secretary of State for the Home Department, 2001). UNHCR has echoed this in its own discussions of how to respond to climate-related displacement (see here and here).  

 

What protections are available to people displaced by climate change?

A response to climate-change related displacement must therefore be sought through other international legal mechanisms. In 2009, the UN Human Rights Council recognised under resolution 10/4 that there is a ‘core inter-linkage between human rights and climate change’ such that those displaced by climate change would be able to rely on the obligations outlined in the ICCPR and the ICESCR. In particular, this would include state’s non-refoulment obligations as the cumulative effect of socio-economic harms can amount to inhumane and degrading treatment such that an individual cannot be returned to such conditions (see Sufi v Elmi, 2011). However, courts may require an immediacy to the rights violation such that future fear of climate-related impacts is insufficient grounds to provide protection from return (see AF(Kiribati), 2013).  

 

In the specific situation of small island states whose territory is threatened by climate change, the law relating to statelessness may also be able to provide some protection and a remedy (see the 1954 Statelessness Convention; Rayfuse 2009). UNHCR has a mandate to prevent and reduce statelessness enabling them to work with states to respond, including coordinating international cooperation, providing protection and resettlement. However, issues concerning when a state will have ceased to exist under international law remains unsettled. For example, for a state to be recognised by international law, Article 1 of the Montevideo Convention requires a permanent population, territory, government and capacity to enter international relations (see Lauterpacht, 1944, and Crawford, 2007, for further discussion). However, there is a lack of clarity on when these criteria will cease to be fulfilled. The problem that international law has grappled with until now has been when new states are formed, not when existing ones have disappeared. As a result, it is unclear when protection for stateless persons of ‘disappeared’ states will be triggered. 

 

There are also regional frameworks that provide broader protections to displaced people, beyond the narrow 1951 definition. In particular, the 1969 OAU Convention Governing the Specific Aspects of Refugee Problems and the 1984 Cartagena Declaration both contain provisions relating to ‘events seriously disturbing public order’, which could be taken to include the events resulting from the effects of climate change. These are both non-binding instruments, whereas Article 5(4) of the Kampala Convention is within a binding instrument and explicitly includes protection for those affected by climate change: 

States parties shall take measures to protect and assist persons who have been internally displaced due to natural or human made disasters, including climate change. 

This focusses protection on internally displaced individuals and ensures that signatory states are required to provides protection and assist those displaced by climate change.  

 

The Kampala Convention is largely based upon the UN Guiding Principles on internal displacement which, under Principle 6(d), outlines that internal displacement is prohibited including in the context of disasters. The principles then provide a framework for states to respond to internal displacement, including that resulting from disasters. The extension of human rights protections to those fleeing climate change is echoed in the Global Compact on Migration, which calls for humanitarian visas for people migrating due to natural disasters and climate change (see objective 2 and 5), as well as similar commitments in the Sustainable Development Goals. Such a response to climate-change related displacement is required under the commitments of Article 14(f) of the Cancun Adaptation of the United Nations Framework Convention on Climate Change (UNFCCC). This aims to enhance understanding, coordination and cooperation with regard to climate change induced displacement…’ These instruments represent moves by the international community to consolidate existing legal frameworks to respond to climate-change related displacement. However, they are not binding treaty law. They demonstrate political commitments not legal obligations. It is evident that, outside the Africa region, mechanisms for protecting individuals from climate-change related displacement are often non-binding and ad-hoc.  

 

The future of climate-related displacement

The term ‘climate refugee’ is conceptually flawed. Such individuals will not constitute refugees for the term ignores the complex causation involved in any displacement, let alone that related to climate change, which in itself is a multi-causal phenomenon. Whilst human rights law, the law relating to statelessness and regional arrangements do provide for some protections to individuals displaced by climate change, these approaches remain disparate and uncoordinated. A lack of clarity can lead to legal loopholes that are abused by states to limit protections.  

 

To respond to this complexity, there are calls for a separate framework for cross-border climate migrants. Commitments within the Global Compact on Migration and the Sustainable Development Goals, as well as the Cancun Agreement, represent attempts by the international community to start to coordinate and elucidate protection for climate-related displacement. However, much more must be done to ensure clarity on the personal, material and temporal scope of protections and obligations for climate change-related displacement. 

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This blog is written by Dr Kathryn Allinson, a Lecturer in Law, University of Bristol Law School. Her research concerns the establishment of state responsibility for breaches of international law focussing on the interaction of human rights and humanitarian law in relation to displacement, and the protection of socio-economic human rights during conflict.  

Kathryn Allinson

 

 

A previous MMB blog by Ignacio Odriozola looked at a landmark decision by the United Nations Human Rights Committee on people seeking international protection due to the effects of climate change: Climate-change displacement: a step closer to human rights protection.  

Foodie for thought

Posted on by janet.crompton

Have you ever wondered how the food you eat impacts climate change? There are all sorts of discussions around energy, transport, green tech, that famous 1.5 ℃, the IPCC… but there is a significantly unspoken polluter that is part of our daily lives, and without which, ironically, we could not live: the food industry. The food industry is one of the biggest contributors to climate change and biodiversity loss, yet food systems have not been given much thought until recently, somehow it was always thought that food “just happens”.

How many of us, when shopping at the supermarket, really think about where everything that is there, nicely placed on the shelves and aisles, comes from? Who packaged your apples? Who flew your avocados from Brazil? Who harvested those avocados from Brazil and how much were they paid? How old was that cow that some factory milked, and who bottled the milk? What is the footprint of that bottle? How much space do cows take? How much soya do they need to grow? How much do cows emit? We could go on forever, but the reality is that not many people really ask those questions at the supermarket, for some, as I said, food happens.

And I feel obliged here to open a short bracket to say that, of course, in reality there will be people who are not even able to ask those questions because it is not their priority. There are often bigger problems in our lives we have to deal with, and it would be unreasonable to ask people who, for example, are struggling to make ends meet to think about what they buy. But on the other hand that is also the point. We have made it incredibly difficult and almost a privilege for people to be able to reflect on their food. So returning to my initial point, how could we blame anyone for not asking all those questions, when we have become so detached from those very people who produce our food, and those places where food is grown?

With food systems becoming ever more complex and globalised, individuals started to lose touch with the reality behind the curtains. We no longer ask the farmer; we ask the label, but how much can a label tell us about what we are buying? Unfortunately, big corporations can often hide behind labels, something that we now call “green-washing”, a fancy word for misleading (and often false) advertising that creates nothing but confusion among consumers, making them believe that they are making a conscious and environmentally friendly choice, when they are not.

One of the biggest controversies in the past few years was around the MSC (Marine Stewardship Council) “Certified Sustainable Seafood” label (that blue tick on tuna cans and other fish sold in supermarkets), which was criticised for setting a very low bar for fisheries to be certified as sustainable, and for its lack of on-site controls and checks. So not only the label allegedly does not guarantee that all efforts have been made to avoid bycatch and seabed damage, but also the fact that fisheries buy the certification from the MSC is for many something that undermines its credibility.

So how can consumers navigate all this information? It would be impossible for people to be able to assess the credibility of every label, stamp, tick on their food, but also unreasonable. The lack of transparency in the food system we are locked-in is a massive flaw, and labels, the way they are handed out now, are not a solution.

There has been much talk about reconnecting with our producers through smaller supply chains, and the idea of buying from their local farmers is something that many probably dream of. How nice would it be to just go to the local market, like the good old days, and buy fresh fruit, vegetables, fresh meat, fresh eggs… all sorts of delicious, good food? It would be great, yes, but probably a utopia for a long time still. Just think of Bristol, a great city with plenty of good food and farmers, a city that has been recognised for its efforts towards a better food system, yet in 2021 about 6.5% of the local population suffered from hunger and 12% struggled to access food. How is this happening in a city so rich of diverse cuisines?

There are many factors that contribute to the rise of food insecurity in Bristol. Covid-19 and the rise in cost of living are maybe the most obvious and recent factors, but generally any inequality can be linked back to poverty and lack of accessibility (which shockingly is a big problem in Bristol). But aside from all of these, something that has an impact on food systems (much more than what many would think) is culture. Systems are ultimately the result of our own ways of doing, ingrained in practice and often locked in, and our ways of doing are inevitably linked to our culture. Now I will not spend time telling you about the history of our food systems and British food culture, because, as a matter of fact, my point is somewhere else. However, in the past few years we have seen the so-called “foodie culture” emerge.

Being a foodie in the simplest terms means that you care about food and are interested about what you eat and where it comes from, which, don’t get me wrong, it is great! Because these people are probably asking those questions that I mentioned at the beginning. However, the problem is that foodie culture has become a very much elitist trend, and with food becoming more and more trendy and catered for foodies, it has now become acceptable to charge stratospheric prices for a burger and chips because the potatoes are organic. Satire aside, it is true, the quality of products should be valued more, and of course products that are produced more sustainably cost more; but this also means that we are telling people who cannot afford to spend more than a certain amount on a good burger with chips that they cannot eat good food.

The fundamental issue of foodie culture is that it has become a trend to eat “fancy” food, which gives businesses the power to price things up, in a way that it becomes exclusionary for people who do not have the privilege of being able to “treat themselves”, and this creates more division. Unfortunately, foodie culture goes hand in hand with a very much criticised characteristic of environmentalism and sustainable living, which is that it is predominantly a (white) middle-class prerogative. Being able to afford to think about sustainability is a privilege, and of course those who are in such fortunate position have the responsibility to act upon it, but what we should not forget is that indeed we are in a position that many could only envy.

There is no way we can create a better and more transparent food system, where people are connected and aware, if all these inequalities still exist. We cannot have a better food system when we live in a cultural setting that leaves half of the population behind, which is perhaps the main message I want to convey. If you have read this far, I hope you will give more thought to what your standpoint and your privileges are. I do wish I had the answers to all these problems I laid out, but there is only so much one can do in a one-year research programme!

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This blog is written by Cabot Institute for the Environment member Sonia Pighini, currently researching people-centred sustainable food system transitions on the Cabot Institute’s Master’s by Research in Global Environmental Challenges at the University of Bristol.

Stockholm+50: No way to have a conversation about climate change

Posted on by janet.crompton

 

I’m just back from Stockholm+50, the summit convened to mark 50 years since the first UN conference on ‘the human environment’ that led to the founding of the UN Environment Programme. Could the participants then have imagined that half a century later we would be living through mass extinctions and still be trying to work out how to stop (some) humans creating a hothouse world?  

Perhaps they would, if they’d seen what these conferences have become. While ‘jaw jaw’ remains better than ‘war war’, there is no doubt that these climate conferences have become a parody performance of international negotiations. Children sang and presented flowers; the UN Secretary General Antonio Gutierrez restated the ‘code red’ call he’s been making for a while now; John Kerry stated publicly that world leaders were on a ‘collective suicide mission’, which, given that he’s the United States Ambassador on Climate Change, should have made more headlines, but was instead greeted with a collective ‘meh’. ‘Interactive’ dialogue sessions promised to open up the agenda, but invited only pre-selected agencies all of whom said, again, what they’d been saying for years.  

 

This is no way to have a conversation.

 

Over two days, ministers and civil servants from every UN country and associated organisations make five minute speeches on the main stage designed to appeal to the media back home rather than make any breakthroughs in the room. There are the usual obligatory selfie walls and hordes of professional sustainability experts in suits taking advantage of them to burnish their green international network credentials. Civil society groups have to fight discriminatory visa systems and lack of funds to even get to the summit, only to find out that there is no access to the processes by which the summit decisions and texts are being made. The youth delegations express their now familiar (and understandable) frustration with the older generation and demand of tired, under-funded UN representatives that they ‘use their privilege’ and power to make the changes needed. It resembles nothing so much as a pyramid selling scheme, with everyone fighting to get closer and closer to a centre of power which, in the end, turns out to be illusory.  

 

As an outsider, watching this process in Stockholm, just as I watched COP last year in Glasgow, was like watching an old world dying. You could see old institutions struggle and fail to deal with state capture by fossil fuel interests, observe exponential natural changes meet incremental policy negotiations, feel the chaotic speed of ecosystem transformations meet lock-in and predatory delay of social systems.  

 

And yet, where there is death there is also, always, life.  

 

All around the official event were people using the summit as an excuse to gather, as a way of using the old systems to create something new. A new generation of policy actors, youth movements, academics, unions and civil society, energised by lessons learned from COP26, gathered in informal associated events and activities. This is where the energy was, where dialogue was taking place, where people were learning from each other and naming the obstacles that needed to be overcome.  

 

You could feel the energy in the work of the Fossil Fuel Non Proliferation Treaty movement which is creating serious alliances across countries and interests and is beginning to exert enough pressure to get commitments to fossil fuel phase-out on the formal agenda; you could see it in the brilliant legal escapades of the ‘Stop Ecocide’ movement making the case for the rights of nature and getting faith leaders around the world signed up to protecting nature. And more than energy, you could see serious, feasible new ideas emerging in the hard economic thinking mobilised by the Stockholm Resilience Centre in their new Earth4all report, which outlines concrete steps towards non-ecocidal and non-suicidal economic arrangements; and in the principled and practical work of the Rainforest Coalition demonstrating what real carbon capture actually looks like and tracing routes towards sustaining it.

 

What characterises many of these activities is a commitment to a different sort of conversation – to processes of unlearning, of listening, of deep attention to others in the room, of naming the hard problems and working together on them. They point the way to a new sort of conversation – one from which the organisers of future UN conferences might learn. And one which we can all begin to model and practice in each country, network or community that we are part of back home.  

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This blog is written by Cabot Institute for the Environment member Keri Facer, Professor of Social and Educational Futures at the University of Bristol.

 

Prehistoric Planet: TV show asked us to explore what weather the dinosaurs lived through

Posted on by janet.crompton
Apple TV+, CC BY-NC-SA

When conjuring up images of when dinosaurs ruled the planet we often think of hot and humid landscapes in a world very different from our own. However, the new TV series Prehistoric Planet, narrated by Sir David Attenborough, shows dinosaurs living and indeed thriving in many types of environments, including colder regions where snowstorms, freezing fog and sea-ice were commonplace.

When the show’s producers first approached us to help understand the kinds of weather and environment that dinosaurs lived in before being wiped out around 66 million years ago, it prompted us to tackle a problem that has existed in palaeoclimate modelling for decades. That was, when scientists like us used computers to simulate, or “model”, the climate of prehistoric Earth, the models tended to make the poles much colder than evidence from fossils and rocks suggested they had actually been.

For the TV series, not only have we improved our models, but we have run the computer programmes for longer than anybody else has ever done to get the models as close to ancient “reality” as possible.

Prehistoric Planet depicts CGI dinosaurs based on the latest research.
AppleTV+, CC BY-NC-SA

The producers, the BBC’s Natural History Unit, needed to know about the weather so they could film “real world” locations similar to those that existed in the past where dinosaurs lived. But most of what we know about the climate that long ago comes from indirect “proxy” evidence, such as leaf fossils and traces of certain chemicals in rocks, which can only reconstruct the average climate over decades or centuries. This is where the narrative of a much hotter and more humid Cretaceous world comes from.

This narrative isn’t exactly wrong, but it doesn’t tell the whole story since weather and climate behave differently. For instance, even in today’s warming world a place like Texas, largely hot and humid, recently experienced widespread snowfall. Geologists a million years from now will spot the sudden global warming – but not the freak snowstorm. Nonetheless, modelling the the prehistoric equivalent of these snowstorms is important since we know warmer worlds will experience greater weather extremes. And these extremes will have largely determined which regions were completely inhospitable to dinosaurs.

Surface wind speed and precipitation through a typical year 69m years ago. An index of 1 means no visibility beyond 10 metres.

How do we know what the weather was like?

Unfortunately, although fossils give us many clues as to past climate, most cannot directly tell us what the weather was on a day to day basis.

So, for a given place on Earth, how do we know what the weather was on, say, May 27 some 66 million years ago? To do this we need to employ a computer simulation of the climate, similar to the ones used to look at future climate change today. These models are based on fundamental physical and biological processes which remain constant with time. It is therefore possible to adjust them for ancient worlds, even if we don’t know precise details like where or how high the mountains were, or exactly how much carbon dioxide was in the atmosphere.

We can then check these models using some of the ancient climate proxies, such as fossilised leaves, coral or rocks which contain traces of what conditions were like at the time. If our model matches up with the proxies – and it did – then we can be confident it is simulating typical weather at the time.

So what did we learn from modelling the climate of 66m years ago?

Our model found there would have been intense blizzards in Antarctica, for instance, “category six” hurricanes (something we are likely to see in our lifetimes) buffeting the mid and low latitudes and extensive, ever present, fog banks creating murky winters under polar cloud caps.

In a warmer world the water cycle is intensified over the poles. This meant more water in the air, and large parts of the planet would have been very foggy almost all the time (Source: modelling work by the authors)

This doesn’t immediately sound like a dinosaur-friendly environment. However, the old misconception that dinosaurs were cold blooded, thus requiring a warm climate for survival has for the most part already been dismissed. The new paradigm is that dinosaurs were warm blooded, and could to some extent regulate their internal temperature, like mammals do today.

This would be essential to survive large swings in temperature, driven by varied weather patterns, particularly in the polar regions. Our modelling therefore backs up recent fossil discoveries which show that some dinosaur species were cold-adapted, could see in low light conditions (useful in those huge fog banks), and thrived year-round near the poles.

Dinosaur in snow
Pachyrhinosaurus surviving and thriving.
AppleTV+, CC BY-NC-SA

The Prehistoric Planet scenes with the chilly Pachyrhinosaurus were set in Alaska, and demonstrate why the show wanted check its accuracy with climate models. We have an idea what the conditions would have been like there 66m years ago thanks to detailed fossils of plants, dinosaurs and other animals, yet the old models would have predicted intensely-cold and lifeless tundra.

Our model instead matches up with the fossil evidence, and predicts forests right up to the margins of the Arctic Ocean at 82°N – much further north than any trees today. In the summer, dinosaur food would have been abundant, but in the long dark winters it would have been more difficult to find, particularly as both fossils and modelling suggests it was so foggy.

Dinosaurs survived for a remarkable 165 million years. Tyrannosaurus Rex lived much closer to present day humans than it did to Stegosauruses, for instance. They managed to survive so long because they were resilient and adaptable to changeable environmental conditions, much like mammals are today. Our work for Prehistoric Planet shows that they were able to survive through greater extremes in temperature, stormier weather, and more extreme droughts than humans have experienced – so far.The Conversation

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This blog is written by Cabot Institute for the Environment members Dr Alex Farnsworth, Senior Research Associate in Meteorology, and Paul Valdes, Professor of Physical Geography, University of Bristol; and Robert Spicer, Emeritus Professor of Earth Sciences, The Open University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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