climate change – Page 4 – Cabot Institute for the Environment blog

Limiting global warming to 2℃ is not enough – why the world must keep temperature rise below 1℃

Posted on June 29, 2023 by amanda.woodman-hardy

Warming of more than 1℃ risks unsafe and harmful outcomes for humanity.
Ink Drop/Shutterstock

The Paris Climate agreement represented a historic step towards a safer future for humanity on Earth when it was adopted in 2015. The agreement strove to keep global heating below 2℃ above pre-industrial levels with the aim of limiting the increase to 1.5℃ if possible. It was signed by 196 parties around the world, representing the overwhelming majority of humanity.

But in the intervening eight years, the Arctic region has experienced record-breaking temperatures, heatwaves have gripped many parts of Asia and Australia has faced unprecedented floods and wildfires. These events remind us of the dangers associated with climate breakdown. Our newly published research argues instead that humanity is only safe at 1℃ of global warming or below.

While one extreme event cannot be solely attributed to global heating, scientific studies have shown that such events are much more likely in a warmer world. Since the Paris agreement, our understanding of the impacts of global heating have also improved.

A fishing boat surrounded by icebergs that have come off a glacier. — Fishing boat dwarfed by icebergs that came off Greenland’s largest glacier, Jakobshavn Isbrae.
Jonathan Bamber, Author provided

Rising sea levels are an inevitable consequence of global warming. This is due to the combination of increased land ice melting and warmer oceans, which cause the volume of ocean water to increase. Recent research shows that in order to eliminate the human-induced component of sea-level rise, we need to return to temperatures last seen in the pre-industrial era (usually taken to be around 1850).

Perhaps more worrying are tipping points in the climate system that are effectively irreversible on human timescales if passed. Two of these tipping points relate to the melting of the Greenland and West Antarctic ice sheets. Together, these sheets contain enough ice to raise the global sea level by more than ten metres.

The temperature threshold for these ice sheets is uncertain, but we know that it lies close to 1.5℃ of global heating above pre-industrial era levels. There’s even evidence that suggests the threshold may already have been passed in one part of west Antarctica.

Critical boundaries

A temperature change of 1.5℃ might sound quite small. But it’s worth noting that the rise of modern civilisation and the agricultural revolution some 12,000 years ago took place during a period of exceptionally stable temperatures.

Our food production, global infrastructure and ecosystem services (the goods and services provided by ecosystems to humans) are all intimately tied to that stable climate. For example, historical evidence shows that a period called the little ice age (1400-1850), when glaciers grew extensively in the northern hemisphere and frost fairs were held annually on the River Thames, was caused by a much smaller temperature change of only about 0.3℃.

A sign marking the retreat of a glacier since 1908. — Jasper National Park, Canada. Glaciers used to grow extensively in the Northern Hemisphere.
Matty Symons/Shutterstock

A recent review of the current research in this area introduces a concept called “Earth system boundaries”, which defines various thresholds beyond which life on our planet would suffer substantial harm. To avoid passing multiple critical boundaries, the authors stress the need to limit temperature rise to 1℃ or less.

In our new research, we also argue that warming of more than 1℃ risks unsafe and harmful outcomes. This potentially includes sea level rise of multiple metres, more intense hurricanes and more frequent weather extremes.

More affordable renewable energy

Although we are already at 1.2℃ above pre-industrial temperatures, reducing global temperatures is not an impossible task. Our research presents a roadmap based on current technologies that can help us work towards achieving the 1℃ warming goal. We do not need to pull a technological “rabbit out of the hat”, but instead we need to invest and implement existing approaches, such as renewable energy, at scale.

Renewable energy sources have become increasingly affordable over time. Between 2010 and 2021, the cost of producing electricity from solar energy reduced by 88%, while wind power saw a reduction of 67% over the same period. The cost of power storage in batteries (for when the availability of wind and sunlight is low) has also decreased, by 70% between 2014 and 2020.

An aerial photograph of a photovoltaic power plant on a lush hillside. — A photovoltaic power plant in Yunnan, China.
Captain Wang/Shutterstock

The cost disparity between renewable energy and alternative sources like nuclear and fossil fuels is now huge – there is a three to four-fold difference.

In addition to being affordable, renewable energy sources are abundantly available and could swiftly meet society’s energy demands. Massive capacity expansions are also currently underway across the globe, which will only further bolster the renewable energy sector. Global solar energy manufacturing capacity, for example, is expected to double in 2023 and 2024.

Removing carbon dioxide from the atmosphere

Low-cost renewable energy will enable our energy systems to transition away from fossil fuels. But it also provides the means of directly removing CO₂ from the atmosphere at a large scale.

CO₂ removal is crucial for keeping warming to 1℃ or less, even though it requires a significant amount of energy. According to research, achieving a safe climate would require dedicating between 5% and 10% of total power generation demand to effective CO₂ removal. This represents a realistic and attainable policy option.

Various measures are used to remove CO₂ from the atmosphere. These include nature-based solutions like reforestation, as well as direct air carbon capture and storage. Trees absorb CO₂ from the atmosphere through photosynthesis and then lock it up for centuries.

A group of people planting a mangrove forest next to the sea. — A mangrove forest being planted in Klong Khone Samut Songkhram Province, Thailand.
vinai chunkhajorn/Shutterstock

Direct air capture technology was originally developed in the 1960s for air purification on submarines and spacecrafts. But it has since been further adapted for use on land. When combined with underground storage methods, such as the process of converting CO₂ into stone, this technology provides a safe and permanent method of removing CO₂ from the atmosphere.

Our paper demonstrates that the tools and technology exist to achieve a safer, healthier and more prosperous future – and that it’s economically viable to do so. What appears to be lacking is the societal will and, as a consequence, the political conviction and commitment to achieve it.

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This blog is written Cabot Institute for the Environment member Jonathan Bamber, Professor of Glaciology and Earth Observation, University of Bristol and Christian Breyer, Professor of Solar Economy, Lappeenranta University of Technology. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Arctic Ocean could be ice-free in summer by 2030s, say scientists – this would have global, damaging and dangerous consequences

Posted on June 8, 2023 by amanda.woodman-hardy

Ice in the Chukchi Sea, north of Alaska and Siberia.
NASA Goddard Space Flight Center

The Arctic Ocean could be ice-free in summer by the 2030s, even if we do a good job of reducing emissions between now and then. That’s the worrying conclusion of a new study in Nature Communications.

Predictions of an ice-free Arctic Ocean have a long and complicated history, and the 2030s is sooner than most scientists had thought possible (though it is later than some had wrongly forecast). What we know for sure is the disappearance of sea ice at the top of the world would not only be an emblematic sign of climate breakdown, but it would have global, damaging and dangerous consequences.

The Arctic has been experiencing climate heating faster than any other part of the planet. As it is at the frontline of climate change, the eyes of many scientists and local indigenous people have been on the sea ice that covers much of the Arctic Ocean in winter. This thin film of frozen seawater expands and contracts with the seasons, reaching a minimum area in September each year.

Animation of Arctic sea ice from space — Arctic sea ice grows until March and then shrinks until September.
NASA

The ice which remains at the end of summer is called multiyear sea ice and is considerably thicker than its seasonal counterpart. It acts as barrier to the transfer of both moisture and heat between the ocean and atmosphere. Over the past 40 years this multiyear sea ice has shrunk from around 7 million sq km to 4 million. That is a loss equivalent to roughly the size of India or 12 UKs. In other words, it’s a big signal, one of the most stark and dramatic signs of fundamental change to the climate system anywhere in the world.

As a consequence, there has been considerable effort invested in determining when the Arctic Ocean might first become ice-free in summer, sometimes called a “blue ocean event” and defined as when the sea ice area drops below 1 million sq kms. This threshold is used mainly because older, thicker ice along parts of Canada and northern Greenland is expected to remain long after the rest of the Arctic Ocean is ice-free. We can’t put an exact date on the last blue ocean event, but one in the near future would likely mean open water at the North Pole for the first time in thousands of years.

Annotated map of Arctic — The thickest ice (highlighted in pink) is likely to remain even if the North Pole is ice-free.
NERC Center for Polar Observation and Modelling, CC BY-SA

One problem with predicting when this might occur is that sea ice is notoriously difficult to model because it is influenced by both atmospheric and oceanic circulation as well as the flow of heat between these two parts of the climate system. That means that the climate models – powerful computer programs used to simulate the environment – need to get all of these components right to be able to accurately predict changes in sea ice extent.

Melting faster than models predicted

Back in the 2000s, an assessment of early generations of climate models found they generally underpredicted the loss of sea ice when compared to satellite data showing what actually happened. The models predicted a loss of about 2.5% per decade, while the observations were closer to 8%.

The next generation of models did better but were still not matching observations which, at that time were suggesting a blue ocean event would happen by mid-century. Indeed, the latest IPCC climate science report, published in 2021, reaches a similar conclusion about the timing of an ice-free Arctic Ocean.

As a consequence of the problems with the climate models, some scientists have attempted to extrapolate the observational record resulting in the controversial and, ultimately, incorrect assertion that this would happen during the mid 2010s. This did not help the credibility of the scientific community and its ability to make reliable projections.

Ice-free by 2030?

The scientists behind the latest study have taken a different approach by, in effect, calibrating the models with the observations and then using this calibrated solution to project sea ice decline. This makes a lot of sense, because it reduces the effect of small biases in the climate models that can in turn bias the sea ice projections. They call these “observationally constrained” projections and find that the Arctic could become ice-free in summer as early as 2030, even if we do a good job of reducing emissions between now and then.

Walruses on ice floe — Walruses depend on sea ice. As it melts, they’re being forced onto land.
outdoorsman / shutterstock

There is still plenty of uncertainty around the exact date – about 20 years or so – because of natural chaotic fluctuations in the climate system. But compared to previous research, the new study still brings forward the most likely timing of a blue ocean event by about a decade.

Why this matters

You might be asking the question: so what? Other than some polar bears not being able to hunt in the same way, why does it matter? Perhaps there are even benefits as the previous US secretary of state, Mike Pompeo, once declared – it means ships from Asia can potentially save around 3,000 miles of journey to European ports in summer at least.

But Arctic sea ice is an important component of the climate system. As it dramatically reduces the amount of sunlight absorbed by the ocean, removing this ice is predicted to further accelerate warming, through a process known as a positive feedback. This, in turn, will make the Greenland ice sheet melt faster, which is already a major contributor to sea level rise.

The loss of sea ice in summer would also mean changes in atmospheric circulation and storm tracks, and fundamental shifts in ocean biological activity. These are just some of the highly undesirable consequences and it is fair to say that the disadvantages will far outweigh the slender benefits.

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.

Why 40°C is bearable in a desert but lethal in the tropics

Posted on June 2, 2023 by amanda.woodman-hardy

Phew: heat plus humidity can make Bangkok an uncomfortable place in a heatwave.
Pavel V.Khon/SHutterstock

This year, even before the northern hemisphere hot season began, temperature records were being shattered. Spain for instance saw temperatures in April (38.8°C) that would be out of the ordinary even at the peak of summer. South and south-east Asia in particular were hammered by a very persistent heatwave, and all-time record temperatures were experienced in countries such as Vietnam and Thailand (44°C and 45°C respectively). In Singapore, the more modest record was also broken, as temperatures hit 37°C. And in China, Shanghai just recorded its highest May temperature for over a century at 36.7°C.

We know that climate change makes these temperatures more likely, but also that heatwaves of similar magnitudes can have very different impacts depending on factors like humidity or how prepared an area is for extreme heat. So, how does a humid country like Vietnam cope with a 44°C heatwave, and how does it compare with dry heat, or a less hot heatwave in even-more-humid Singapore?

Weather and physiology

The recent heatwave in south-east Asia may well be remembered for its level of heat-induced stress on the body. Heat stress is mostly caused by temperature, but other weather-related factors such as humidity, radiation and wind are also important.

Our bodies gain heat from the air around us, from the sun, or from our own internal processes such as digestion and exercise. In response to this, our bodies must lose some heat. Some of this we lose directly to the air around us and some through breathing. But most heat is lost through sweating, as when the sweat on the surface of our skin evaporates it takes in energy from our skin and the air around us in the form of latent heat.

annotated diagram of person — How humans heat up and cool down.
Take from Buzan and Huber (2020) Annual Review of Earth and Planetary Sciences, Author provided

Meteorological factors affect all this. For example, being deprived of shade exposes the body to heat from direct sunlight, while higher humidity means that the rate of evaporation from our skin will decrease.

It’s this humidity that meant the recent heatwave in south-east Asia was so dangerous, as it’s already an extremely humid part of the world.

The limit of heat stress

Underlying health conditions and other personal circumstances can lead to some people being more vulnerable to heat stress. Yet heat stress can reach a limit above which all humans, even those who are not obviously vulnerable to heat risk – that is, people who are fit, healthy and well acclimatised – simply cannot survive even at a moderate level of exertion.

One way to assess heat stress is the so-called Wet Bulb Globe Temperature. In full sun conditions, that is approximately equivalent to 39°C in temperature combined with 50% relative humidity. This limit will likely have been exceeded in some places in the recent heatwave across south-east Asia.

In less humid places far from the tropics, the humidity and thus the wet bulb temperature and danger will be much lower. Spain’s heatwave in April with maximum temperatures of 38.8°C had WBGT values of “only” around 30°C, the 2022 heatwave in the UK, when temperatures exceeded 40°C, had a humidity of less than 20% and WBGT values of around 32°C.

Two of us (Eunice and Dann) were part of a team who recently used climate data to map heat stress around the world. The research highlighted regions most at risk of exceeding these thresholds, with literal hotspots including India and Pakistan, south-east Asia, the Arabian peninsula, equatorial Africa, equatorial South America and Australia. In these regions, heat stress thresholds are exceeded with increased frequency with greater global warming.

In reality, most people are already vulnerable well below the survivability thresholds, which is why we can see large death tolls in significantly cooler heat waves. Furthermore, these global analyses often do not capture some very localised extremes caused by microclimate processes. For example a certain neighbourhood in a city might trap heat more efficiently than its surroundings, or might be ventilated by a cool sea breeze, or be in the “rain shadow” of a local hill, making it less humid.

Variability and acclimatisation

The tropics typically have less variable temperatures. For example, Singapore sits almost on the equator and its daily maximum is about 32°C year round, while a typical maximum in London in mid summer is just 24°C. Yet London has a higher record temperature (40°C vs 37°C in Singapore).

Given that regions such as south-east Asia consistently have high heat stress already, perhaps that suggests that people will be well acclimatised to deal with heat. Initial reporting suggests the intense heat stress of the recent heatwave lead to surprisingly few direct deaths – but accurate reporting of deaths from indirect causes is not yet available.

On the other hand, due to the relative stability in year-round warmth, perhaps there is less preparedness for the large swings in temperature associated with the recent heatwave. Given that it is not unreasonable, even in the absence of climate change, that natural weather variability can produce significant heatwaves that break local records by several degrees Celsius, even nearing a physiological limit might be a very risky line to tread.

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This blog is written by Cabot Institute for the Environment members: Dr Alan Thomas Kennedy-Asser, Research Associate in Climate Science; Professor Dann Mitchell, Professor of Climate Science, and Dr Eunice Lo, Research Fellow in Climate Change and Health, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Degrowth isn’t the same as a recession – it’s an alternative to growing the economy forever

Posted on May 24, 2023 by amanda.woodman-hardy

The UK economy unexpectedly shrank by 0.3% in March, according to the Office of National Statistics. And though the country is likely to narrowly avoid an official recession in 2023, just as it did the previous year, the economy is projected to hit the worst growth rates since the Great Depression, and the worst in the G7.

For many people, this certainly feels like a recession, with food prices soaring and pay falling dramatically below inflation meaning many people are having to reduce their standard of living.

Against this backdrop, the main political parties are focused on delivering economic growth for a better future. One of Prime Minister Rishi Sunak’s five priorities for 2023 is simply “growing the economy”, while opposition leader Keir Starmer has pledged to turn the UK into the fastest growing G7 economy.

Sunak and Starmer’s priorities reflect conventional economic wisdom that “growth, growth, growth” increases incomes and standards of living, employment and business investment. When the economy doesn’t grow, we see unemployment, hardship and inequality.

Growth cannot solve everything

However, economic growth on its own is not going to solve these multiple and intersecting crises, as it only counts the total value of goods and services produced without measuring qualitative change – whether this stuff makes you feel happy or secure.

TVs in a shop — GDP measures things not feelings.
Luckies / shutterstock

In contrast, an increasing number of policymakers, thinkers and activists argue for abandoning our obsession with growth at all costs. Instead of pursuing GDP growth, they suggest orienting the economy towards social equality and wellbeing, environmental sustainability and democratic decision making. The most far reaching of those proposals are made under the umbrella term of degrowth.

Degrowth is a set of ideas and a social movement that presents a comprehensive solution to these issues. The pandemic demonstrated that a new normal can be achieved at pace, as we saw sweeping changes to how many of us lived, worked, and travelled.

At the time, headlines equated the pandemic-related GDP squeeze with the perceived “misery of degrowth”. With persistently high inflation rates and the cost of living still spiralling, these debates are going to resurface.

Degrowth is not the same as shrinking GDP

To begin with, degrowth is not the same as negative GDP growth. Instead, degrowth envisions a society in which wellbeing does not depend on economic growth and the environmental and social consequences of its pursuit. Degrowth proposes an equitable, voluntary reduction of overconsumption in affluent economies.

Equally important is to shift the economy away from the ecologically and socially harmful idea that producing more stuff is always good. Instead, economic activity could focus on promoting care, cooperation and autonomy, which would also increase wellbeing and give people a bigger say in how their lives are run.

Yet, for many people the word smacks of misery and the type of frugality they are trying to escape from during the cost of living crisis.

But degrowth, if successfully achieved, would arguably feel better than a recession or a cost-of-living crisis. Here are three reasons why:

1. Degrowth is democratic

The first is the undemocratic and unplanned nature of a recession or cost-of-living crisis. Most citizens would agree, for example, that they had little to no control over the deregulation of the finance industry, and subsequent boom in sub-prime mortgage lending and derivatives trading that caused the 2008/09 financial crash.

Cranes in skyline — Things would still be built – but not just to satisfy a need for growth.
Oleg Totskyi / shutterstock

Degrowth, on the other hand, is a profoundly democratic project. It emphasises direct democracy and deliberation, which means citizens can shape which economic sectors are decreased and by how much, and which ones will grow and by how much.

One example of such a democratic endeavour is the Climate Assembly UK, whose 108 members were selected through a civic lottery process and were broadly representative of the population. After listening to expert testimony, the assembly issued a number of recommendations to support the UK’s net zero climate target. Over a third of all members prioritised support for sustainable growth. Economic growth itself was not among the top 25 priorities.

2. Degrowth would be egalitarian

Recessions, especially when coupled with fiscal austerity, tend to amplify existing inequalities by hitting the poorest members of society first, including women, working-class communities and ethnic minorities.

Degrowth drastically differs from a recession because it is a redistributive project. For instance, a universal basic income), an unconditional monthly state payment to all citizens, is a popular policy with degrowthers.

The degrowth vision is that basic income should guarantee a dignified living standard, remunerate unpaid care, and provide access to healthcare, food and accommodation for those in need. It could be financed by “climate income” schemes that tax carbon and return revenues to the public.

3. Degrowth wouldn’t hinder climate action

In an economy reliant on growth, a recession is generally bad news for the environment.

For instance, for the UK to hit its net zero targets, it must make annual public investments of between £4 billion and £6 billion by 2030. A recession would threaten public spending as well as the confidence investors have in low carbon developments in transport, housing or energy.

But such investments do not have to depend on growth but could instead be made through collective and democratic decisions to make climate action a priority. Carbon taxes will play a large part in this, as will stopping fossil fuel subsidies like the £3.75 billion tax break granted to develop the Rosebank oil and gas field in the sea north of Scotland.

To make sure we stay within the environmental limits within which we can safely operate, sometimes known as our planetary boundaries, degrowth suggests democratically establishing limits on resource use. For example, global greenhouse gas emissions or non-renewable energy use could be capped at a given level, and decline annually.

Sharing these resource “caps” among the population would ensure that while we stay within these safe environmental spaces, everyone has equitable access to the resources required to lead a fulfilling life. In contrast to the pursuit of endless growth, degrowth puts both climate action and human wellbeing at its heart.

This blog is written by Cabot Institute for the Environment member, Dr Katharina Richter, Lecturer in Climate, Politics and Society, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Intense downpours in the UK will increase due to climate change – new study

Posted on March 8, 2023March 8, 2023 by amanda.woodman-hardy

A flash flood in London in October 2019.
D MacDonald/Shutterstock

Elizabeth Kendon, University of Bristol

In July 2021, Kew in London experienced a month’s rain in just three hours. Across the city, tube lines were suspended and stations closed as London experienced its wettest day in decades and flash floods broke out. Just under two weeks later, it happened again: intense downpours led to widespread disruption, including the flooding of two London hospitals.

Colleagues and I have created a new set of 100-year climate projections to more accurately assess the likelihood of heavy rain downpours like these over the coming years and decades. The short answer is climate change means these extreme downpours will happen more often in the UK – and be even more intense.

To generate these projections, we used the Met Office operational weather forecast model, but run on long climate timescales. This provided very detailed climate projections – for every 2.2km grid box over the UK, for every hour, for 100 years from 1981 to 2080. These are much more detailed than traditional climate projections and needed to be run as a series of 20-year simulations that were then stitched together. Even on the Met Office supercomputer, these still took about six months to run.

We ran 12 such 100-year projections. We are not interested in the weather on a given day but rather how the occurrence of local weather extremes varies year by year. By starting the model runs in the past, it is also possible to verify the output against observations to assess the model’s performance.

At this level of detail – the “k-scale” – it is possible to more accurately assess how the most extreme downpours will change. This is because k-scale simulations better represent the small-scale atmospheric processes, such as convection, that can lead to destructive flash flooding.

The fire service attending to a vehicle stuck in floodwater. — Flash flooding can be destructive.
Ceri Breeze/Shutterstock

More emissions, more rain

Our results are now published in Nature Communications. We found that under a high emissions scenario downpours in the UK exceeding 20mm per hour could be four times as frequent by the year 2080 compared with the 1980s. This level of rainfall can potentially produce serious damage through flash flooding, with thresholds like 20mm/hr used by planners to estimate the risk of flooding when water overwhelms the usual drainage channels. Previous less detailed climate models project a much lower increase of around two and a half times over the same period.

We note that these changes are assuming that greenhouse gas emissions continue to rise at current rates. This is therefore a plausible but upper estimate. If global carbon emissions follow a lower emissions scenario, extreme rain will still increase in the UK – though at a slower rate. However, the changes are not inevitable, and if we emit less carbon in the coming decades, extreme downpours will be less frequent.

The increases are significantly greater in certain regions. For example, extreme rainfall in north-west Scotland could be almost ten times more common, while it’s closer to three times more frequent in the south of the UK. The greater future increases in the number of extreme rainfall events in the higher resolution model compared with more traditional lower resolution climate models shows the importance of having k-scale projections to enable society to adapt to climate change.

As the atmosphere warms, it can hold more moisture, at a rate of 7% more moisture for every degree of warming. On a simple level, this explains why in many regions of the world projections show an increase in precipitation as a consequence of human-induced climate change. This new study has shown that, in the UK, the intensity of downpours could increase by about 5% in the south and up to about 15% in the north for every degree of regional warming.

Group of girls with an umbrella walking through a city. — The projected increase in the intensity of rainfall is significantly greater in certain regions.
NotarYES/Shutterstock

However, it is far from a simple picture of more extreme events, decade by decade, as a steadily increasing trend. Instead, we expect periods of rapid change – with records being broken, some by a considerable margin – and periods when there is a pause, with no new records set.

This is simply a reflection of the complex interplay between natural variability and the underlying climate change signal. An analogy for this is waves coming up a beach on an incoming tide. The tide is the long-term rising trend, but there are periods when there are larger waves, followed by lulls.

Despite the underlying trend, the time between record-breaking events at the local scale can be surprisingly long – even several decades.

Our research marks the first time that such a high-resolution data set has spanned over a century. As well as being a valuable asset for planners and policymakers to prepare for the future, it can also be used by climate attribution scientists to examine current extreme rainfall events to see how much more likely they will have been because of human greenhouse gas emissions. The research highlights the importance of meeting carbon emissions targets and also planning for increasingly prevalent extreme rainfall events, which to varying degrees of intensity, look highly likely in all greenhouse gas emissions scenarios.

The tendency for extreme years to cluster poses challenges for communities trying to adapt to intense downpours and risks infrastructure being unprepared, since climate information based on several decades of past observations may not be representative of the following decades.

This blog is written by Cabot Institute for the Environment member Elizabeth Kendon, Professor of Climate Science, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

COP27: Egyptian student perspectives and insight

Posted on February 20, 2023March 3, 2023 by amanda.woodman-hardy

One of the privileges of being a student at the University of Bristol (UoB) is belonging to a diverse academic community comprised of students from many cultural, social and religious backgrounds. With the hosting of COP27 in Egypt this year, the Sustainability Network sought the opportunity to gain insight and perspectives first-hand from Egyptian UoB students around the significance and implications of the climate change focused conference being hosted in their country. Below is a recount of the respondents’ views and opinions.

Disclaimer: Views do not represent the University of Bristol nor the Sustainability Network. Names have been removed to protect the anonymity and privacy of the students who chose to speak.

The significance of climate change

Climate change is one of the most important issues the world is currently facing and will have wide ranging impacts that will influence our daily lives. Climate change, however, is often viewed as a future concern to be dealt with later – despite consequences and impacts thereof already being felt globally and locally making it a current and time sensitive issue. Climate change is also a complex, intersectional issue which coincides with issues of race, class, gender and inequality to name a few. The importance of speaking about climate change, even as non-experts, was highlighted by respondent A. Ultimately, as shared by respondent C, when thinking about climate change, we need to remember that the Earth is our only home (for now) and should be treated with care as we are borrowing it from future generations.

Climate change and Egypt

All respondents shared that either they themselves, or their families, have directly been affected by the impacts of climate change in Egypt. Respondent C shared that when speaking to parents and grandparents about the historical climate of Egypt, many changes to patterns and averages can be observed. This is in line with the scientific evidence that extreme weather events are getting more frequent, severe and widespread. Recurrent examples of climate change risks for Egypt mentioned by respondents and aligning to scientific consensus include:

Heat – Extreme temperatures driven by global warming impact the physical heat tolerance of individuals as well as affects infrastructure and agriculture negatively. Unlike other regional players who have the financial capacity for adaptation measures such as ubiquitous air conditioning, Egypt has less financial and infrastructural resilience to this concern.

Water scarcity – Water supply is a major a concern given climate change driven changing rainfall patterns in what is already an arid country. This issue was linked to regional geopolitical issues such as the contentious building of dams in nearby countries that alter regional water availability patterns.

Food security – The climate change risk to agriculture as a livelihood as well as for food availability was highlighted. The transboundary nature of climate change was reiterated as negative impacts to agriculture could affect food exports such as citrus and grains, thereby impacting global food supply chains. Should agriculture be detrimentally impacted, the cost of food associated with increasing food import dependency for Egypt would also impact local Egyptian food security as food would become less affordable.

Flooding – The threat of sea level rise as well as storm related flooding is of major concern, with many locations having limited financial and infrastructural adaptation capacity, thus posing a risk to infrastructure and human lives. The concerns of climate change refugees and regional migration motivated by climatic and economic variables were brought out in these discussions, once again demonstrating the global scope of climate change concerns.

Air pollution – Air quality, particularly in densely populated areas, is a major concern. Respondents attributed this to overpopulation, major car usage prevalence and general city congestion. Air pollution has health concerns as well as impacts natural weather patterns.

Despite first hand experiences and the extreme risks faced by many communities – particularly coastal communities such as Alexandria and densely populated regions such as Cairo – many respondents noted that climate change has not been a major focus for the Egyptian government over the past few years. This was perceived to be a result of conflicting urgent priorities such as unemployment, healthcare, poverty and education, as well as limited financial capacity and/or political will to address climate change simultaneously to these issues. It was pointed out that there are often financial incentives behind government investment decisions, with money often only being invested into projects that would see immediate returns. Others pointed out, however, that there has been significant progress made over recent years including reductions in plastic consumption, better waste management, investment into sustainable energy sources and biodiversity protection programs. Concerns around political stability and corruption hampering climate change action were noted – in line with the concerns of many LEDCs (Less Economically Developed Countries). The links between climate change and social disparities were demonstrated as the poorest and most vulnerable people would likely be impacted by climate change first.

The COP27 Conference

Respondents shared mixed feelings about the hosting of COP27 in Egypt. On one hand, this event does represent a significant geopolitical win and the bringing of Egypt and the MENA region to the global stage. This was a source of great pride to respondents, as representation of non-western countries in these typically Eurocentric global discussions was viewed to matter greatly. Moreover, the potential benefits to tourism and shaping of perceptions of Egypt as an innovative, up-and-coming and metropolitan country were seen to be positive. On the other hand, some respondents shared concerns about the efficacy of previous COP conferences and noted that the event tends to be overhyped and lead to very little meaningful impact – with goals of previous conferences such as a 1.5⁰C warning reduction targets not on track to being met. The risk of the conference becoming a blame-game or having little effect on the behaviour of large corporations that hold significant power were also mentioned. This COP conference is therefore viewed a make-or break opportunity in the climate change battle. Hopes for the setting of ambitious standards and legal precedents were shared. All respondents concluded by hoping this conference would be different and better than previous conferences, leading to tangible change and positive outcomes. (see the Sustainability Network Post-COP debrief for a reflection on the conference).

Looking forward

So where to from here? Whilst climate change is a global issue that will affect different places in different ways, respondents noted that everyone has a role to play in reaching towards a common goal. Respondent A reflected on the importance of critical thinking and communication, reminding us that disagreement is a common phenomenon that can be leveraged to understand the opinions and perspectives of others. All respondents reflected on the importance of education and awareness surrounding climate change. There were concerns surrounding the influence that COVID-19, the Russia-Ukraine conflict and other socioeconomic or geopolitical current affairs may have on the success of climate change action.

Generally, respondents reiterated the importance of incremental change and encouraged action and implementation over policies and legislation. The importance of international collaboration was revealed, as movements are stronger when we all work together and leverage the unique strengths of individuals and countries alike. Respondent C encouraged us to hold governments accountable, because as they pointed out, if we don’t, who will? The success of the COP27 conference will likely only be seen retroactively over longer time scales, so whilst one respondent urged dramatic outcomes and action to come from the discussions, another respondent viewed success as even one person acting better.

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The Sustainability Network thanks the respondents for their time, honesty and patriotism. The kindness, care and passion of the Egyptian people was well demonstrated and we definitely want to visit the incredible beauty and culture of Egypt you shared with us.

Climate change is threatening Madagascar’s famous forests – our study shows how serious it is

Posted on January 20, 2023March 27, 2023 by amanda.woodman-hardy

Urgent action is needed to protect Madagascar’s forests.
Rijasolo/AFP via Getty Images

Global climate change doesn’t only cause the melting of polar ice caps, rising sea levels and extreme weather events. It also has a direct effect on many tropical habitats and the animals and plants that inhabit them. As fossil fuel emissions continue to drive climate change, large areas of land are forecast to become much hotter and drier by the end of this century.

Many ecosystems, including tropical forests, wetlands, swamps and mangroves, will be unable to cope with these extreme climatic conditions. It is highly likely that the extent and condition of these ecosystems will decline. They will become more like deserts and savanna.

The island nation of Madagascar is of particular concern when it comes to climate change. Of Madagascar’s animal species, 85% cannot be found elsewhere on Earth. Of its plant species, 82% are unique to the island. Although a global biodiversity hotspot, Madagascar has experienced the highest rates of deforestation anywhere in the world. Over 80% of its original forest cover has already been cleared by humans.

This has resulted in large population declines in many species. For example, many species of lemurs (Madagascar’s flagship group of animals) have undergone rapid population decline, and over 95% of lemur species are now classified as threatened on the International Union for Conservation of Nature (IUCN) Red List.

Drier conditions brought about by climate change have already resulted in widespread bush fires throughout Madagascar. Drought and famine are increasingly severe for the people living in the far south and south-western regions of the island.

Madagascar’s future will likely depend profoundly on how swiftly and comprehensively humans deal with the current climate crisis.

What we found

Our study investigated how future climate change is likely to affect four of Madagascar’s key forest habitat types. These four forest types are the dry deciduous forests of the west, humid evergreen forests of the east, spiny bush forests of the arid south, and transitional forests of the north-west corner of the island.

Using computer-based modelling, we simulated how each forest type would respond to climate change from the current period up to the year 2080. The model used the known distribution of each forest type, and current and future climatic data.

We did this under two different conditions: a mitigation scenario, assuming human reliance on greenhouse gas reduces according to climate commitments already made; and an unmitigated scenario, assuming greenhouse gas emissions continue to increase at their current rate.

Our results suggest that unmitigated climate change will result in declines of Madagascar’s forests. The area of land covered by humid forest, the most extensive of the four forest types, is predicted to decrease by about 5.66%. Dry forest and spiny bush are also predicted to decline in response to unmitigated climate change. Transitional forest may actually increase by as much as 5.24%, but this gain will almost certainly come at the expense of other forest types.

We expected our model to show that mitigating climate change would result in net forest gain. Surprisingly, our results suggest entirely the opposite. Forest occurrence will decrease by up to 5.84%, even with efforts to mitigate climate change. This is because global temperatures are forecast to increase under both mitigated and unmitigated scenarios.

These predicted declines are in addition to the huge losses of forest already caused by ongoing deforestation throughout the island.

It looks as if the damage has already been done.

Climate change, a major threat

The results of our research highlight that climate change is indeed a major threat to Madagascar’s forests and likely other ecosystems worldwide. These findings are deeply concerning for the survival of Madagascar’s animals and plants, many of which depend entirely on forest habitat.

Not only will climate change decrease the size of existing forests, changes in temperature and rainfall will also affect the amount of fruit that trees produce.

A Lemur on tree in the forest. — Madagascar lemurs and other animal and plant species may become extinct if the forests disappear.
Rijasolo/AFP

Many of Madagascar’s animals, such as its lemurs, rely heavily on fruit for food. Changes in fruit availability will have serious impact on the health, reproductive success and population growth of these animals. Some animals may be able to adapt to changes in climate and habitat, but others are very sensitive to such changes. They are unlikely to survive in a hot, arid environment.

This will also have serious knock-on effects for human populations that depend on forests and animals for eco-tourism income. Approximately 75% of Madagascar’s population depends on the forest and subsistence farming for survival, and the tourism sector contributes over US$600 million towards the island’s economy annually.

To ensure that Madagascar’s forests survive, immediate action is needed to end deforestation, protect the remaining patches of forest, replant and restore forests, and mitigate global carbon emissions. Otherwise these remarkable forests will eventually disappear, along with all the animals and plants that depend on them.

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This blog is written by Daniel Hending, Postdoctoral Research Assistant Animal Vibration Lab, University of Oxford and Cabot Institute for the Environment member Marc Holderied, Professor in Sensory Biology, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Marc Holderied

Detectable impacts of Climate Change in the UK; a new review for the next Climate Change Risk Assessment

Posted on January 17, 2023March 29, 2023 by janet.crompton

2022 was another year of “unprecedented” weather. Provisional figures indicate that it was the warmest so far recorded, with almost every month hotter than average. Much of the country had a notably mild New Year, despite the cold snap in mid-December. This was preceded by the third warmest autumn on record, and that by a scorching summer, with the hottest day ever recorded in July. But summer’s heat waves were also accompanied by a rise in the number of daily deaths across the country. People around the world are becoming increasingly more aware of events like these, and their impact in the UK is particularly concerning amidst the ongoing cost-of-living, energy, and NHS crises.

Aerial view of the Wennington wildfire, London, 19 July 2022. Source: Harrison Healey, Wikimedia Commons (CC BY 3.0).

Ahead of the Fourth UK Climate Change Risk Assessment (CCRA4), the Climate Change Committee (CCC) are asking what we know about the impact of past and present climate change on natural and human systems here in the UK specifically. At the global level, the 2021 IPCC sixth assessment working group I (AR6 WGI) report concluded: “It is unequivocal that human influence has warmed the atmosphere, ocean and land.” This single sentence has been informed by decades of research by people at the cutting edge of climate science, and the evidence to support it has grown stronger in every IPCC report since they began. The report goes on to say: “Human-induced climate change is already affecting many weather and climate extremes in every region across the globe.” In last year’s follow-up AR6 WGII report on impacts, adaptation, and vulnerability, an extensive assessment of the science led to the conclusion that the magnitude and proliferation of extremes caused by human-induced climate change were having widespread, adverse impacts on both nature and people. Last summer’s heatwaves, and the concurrent dangers to health, homes, and the environment, were a graphic illustration of the nature of such human-induced impacts.

The study of impacts that informed this conclusion is the remit of climate scientists who specialise in “detection and attribution”. This is about looking at what is changing around us and being able to pinpoint the cause(s) – and particularly, whether human-induced climate change is at the root. To inform CCRA4, the CCC have commissioned a joint Bristol and Exeter University team to conduct a comprehensive review of the detection and attribution of climate change in the UK. The first part will cover the detection and attribution of weather and climate changes in the UK, relevant to specific “Climate Impact Drivers”. The second will cover attribution of impacts on societal, infrastructural, economic, and biodiversity sectors. We aim to find out what studies have been done so far, where the gaps are, and whether they can be filled, or if they would require substantial new methodological or data advances. We aim to identify variables which are key drivers of multiple impacts, and, importantly, where further attribution analysis is needed – especially when the impacts are critical for UK risk.

Detection and attribution is a rapidly evolving field, with focus only relatively recently moving from meteorological attribution (e.g., weather extremes) to impact attribution (e.g., consequences for humans and ecosystems). Our systematic review of the literature and final report will be key to tying it all together, especially with the UK focus required by the CCC. But to be able to present the most up-to-date findings, and thus make informed recommendations, we need to ensure that we have considered all relevant studies. So, if you, or someone you know, has published on this topic – whether UK specific or not – we’d like to know about it! Help shape and inform the next UK Climate Change Risk Assessment.

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This blog was written by Regan Mudhar, Professor Dann Mitchell (University of Bristol), Professor Richard Betts and Professor Peter Stott (University of Exeter/UK Met Office).

Four ways winter heatwaves affect humans and nature

Posted on January 11, 2023April 14, 2023 by janet.crompton

Temperature anomaly in Europe, Jan 1. Much of the continent was 10°C or more (dark red and grey) above the long-term average.
WX Charts, CC BY-NC

An extreme winter heatwave meant countries across Europe experienced a record-breaking New Year’s Day. New daily temperature records for the month of January were set in at least eight countries: Belarus, Czechia, Denmark, Latvia, Liechtenstein, Lithuania, Netherlands and Poland.

In many cases the temperatures were not just breaking the old highs, but smashing them by massive margins. On a typical January day in Warsaw, Poland, temperatures would barely go above freezing, yet the city recently experienced 19℃, breaking the previous January high by 5.1℃.

New January records were set at thousands of individual stations in many other countries such as 25.1℃ at Bilbao airport in Spain, 0.7℃ hotter than the previous record set only last year. Large areas of central and Eastern Europe experienced temperatures 10℃ to 15℃ warmer than average for this time of year – and that has persisted through the week.

When Europe experienced extreme heat in July of last year, more than 20,000 died. Fortunately winter heatwaves are much less deadly, but they can still affect both human society and natural ecosystems in many ways.

1. Less energy is needed

In Europe deaths due to cold weather vastly outweigh those caused by extreme high temperatures – in the UK there are ten times more. Warmer winters will reduce this excess mortality and, with the current cost-of-living crisis, many will have been relieved that a heatwave meant less energy was needed to heat their homes.

Electricity demand is influenced by things like the time of day, the day of the week and socio-economic factors like the COVID pandemic or the war in Ukraine. The weather also makes a difference. For example, in Poland and the Netherlands demand was noticeably lower than average, especially since January 1 was a Sunday. The extent of the heatwave also meant countries could refill some of their winter gas reserves, or large batteries.

Energy consumption in Poland December 28 to January 5. The red line shows the 2022-2023 heatwave period, and the grey lines show available data from 2015-2022.
Hannah Bloomfield / data: transparency.entsoe.eu, Author provided

2. Reduced yields for some crops

Winter warm spells don’t always have such a positive impact though. For instance a lack of snow in the mountains affects agriculture and can reduce crop yield, since snow creates an insulating blanket that prevents frost from penetrating into the soil. This means snow can actually increase soil moisture more than rainfall, thus improving growing conditions later in the season.

The big snow melt in spring time replenishes reservoirs and allows hydroelectricity generation, but unexpected snow melt can lead to flooding. Changes to the timings of these events will require preparation and adaptation to enable a steady supply of water to where we need it.

Warmer temperatures will create longer growing seasons in many regions. This is not always the case though. A recent study showed that for alpine grasslands an earlier growing season (the point when snow has melted entirely) leads to ageing and browning of the grasses in the later part of the summer.

3. The snow economy is in trouble

The heatwave caused ski resorts across the Alps to close in what should be their busiest time of year. In January the slopes would be expected to have a good covering of snow – but instead we saw green grassy fields.

This hits the local economy where many people rely on winter sports tourism. Events such as the Adelboden alpine ski World Cup are relying on artificial snow, which comes with a further environmental cost increasing the carbon footprint of ski resorts and requiring a large water supply. Indeed, the Beijing winter Olympics used the equivalent of daily drinking water for 900 million people to generate the artificial snow it required.

4. Animals out of sync with the climate

We humans are perhaps fortunate, as we are able to adapt. Some ski resorts have already opened mountain bike trails in winter to offer alternative tourism, but wildlife and ecosystems cannot adjust so rapidly.

In the mountains many species, such as ptarmigan and mountain hares, change their colouring for winter to camouflage in the white snow. The timing of this change is determined by length of day – not the temperature or amount of snow. These creatures are at greater risk of being preyed on when it is warmer.

White rabbit, brown background — Mountain hares are dressed for a climate that has changed.
Mark Medcalf / shutterstock

Over the past century heat extremes in Europe have increased in intensity and frequency. Both the general warming and heatwave events have been firmly attributed to humans.

Future projections suggest these trends will continue and heatwaves in both summer and winter will get hotter, last longer, and occur more often. We need to learn to adapt for these changes in all seasons and think about the impacts on everyone – and everything – on our planet.

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This blog is written by Cabot Institute for the Environment members Dr Vikki Thompson, Senior Research Associate in Geographical Sciences, University of Bristol and Dr Hannah Bloomfield, Postdoctoral Researcher in Climate Risk Analytics, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

After COP27, is 1.5C still alive?

Posted on December 2, 2022April 16, 2023 by janet.crompton

Try booking a train on Boxing Day in the UK and you’ll soon find out that none are running. Well, not entirely. One small railway line managed by indomitable Gauls still holds out: The Eurostar. And airports are still being served as plains are still flying. Obvs. If this is not just the present, but also our future, then Mia Mottley, Prime Minister of Barbados, is right: “We’re at 1.2 degrees now. If in 5 years we’re at 1.5, then we’re…. we’re…. I won’t use that word now.”

Apologies, I got carried away. Back to planes (flying), trains (not running) and automobiles (driving). These are symptomatic of the mess we’re in, but nothing compared to the mess we’re heading towards. And nothing compared to the mess others already find themselves in. If these current trends continues the number of refugees is set to increase from 21m in 2022 to 1bn in 2050 (Mia Mottley again). Many originate from Africa which is responsible for only 4% of global emissions (and 2% of historic emissions) and home to 600m without access to electricity.

While inanimate capital moves freely across borders, refugees are increasingly prevented from doing so. As their poverty and desperation grows in a warming world, their cost of borrowing increases as the World Bank uses per capita income as a proxy for borrowing conditions. Consequently, such countries (Least Developed Countries – LDCs) borrow at 12-14% while rich countries (the G7) borrow at 1-4%. According to Indian economist Joyashree Roy, these countries need 7% growth per year to escape their plight but if they are borrowing at +10% cost of capital, this growth will not be powered by renewables.

Neither will the focusing on the supply of renewables alone deliver Sustainable Development Goals (SDGs). Demand-side interventions are necessary to shift investment patterns and create new economic opportunities that are synergistic with SDGs. But all this depends on infrastructure access and empowerment to make the right choices, which in turn are determined by the flow of finance. To put on track for 1.5C, these flows need to quadruple to $4-6trn per year, according to Macky Sall, Senegalese President and current Chairperson of the African Union. IPCC Chair Hoesung Lee, goes one step further: access to capital is the key determinant of limiting global warming to 1.5C. Concessional access to finance was provided during COVID, as Mia Mottley pointed out, so why can it not be provided to prevent climate catastrophe?

Dr Colin Nolden (left) at COP27 with IPCC Chair Hoesung Lee and Dr Alix Dietzel

On the plus side, outgoing COP26 President Alok Sharma suggests that 90% of global emissions are covered by a net zero target. Almost 1/3rd of the global population who accumulate 55% of global GDP are covered by Emissions Trading Schemes, according to Stefano de Clara, Head of the International Carbon Action Partnership. Then again, the current average carbon price stands at $6/t. This needs to increase to $75/t by 2030 to limit warming to 2C, not to mention 1.5C, according to Dora Benedek from the International Monetary Fund.

Without such a massive increase in the cost of carbon, emissions are expected to be only 12% (6GtCO2eq) lower in 2030 compared to today. What about magic??, you might interject at this point. Current Carbon Capture and Storage (CCS) and Direct Air Capture (DAC) capacities amount to around 4 hours of global emissions and are projected to amount to around 16 hours in 2030, according to Sven Teske from the University of Technology Sydney. To keep 1.5C alive, we need to reduce emissions by 30-50% in by 2030 (Dora Benedek again). So yes to magic, but only within the bounds of Kate Raworth’s famous doughnut.

And it’s both sides of that tasty doughnut that we need to bear in mind. On the outside, quick wins are possible regarding methane emissions which are responsible for around 0.5C of the 1.2C we stand above pre-industrial levels. Around 0.1C of warming can be addressed by cutting gas flaring and coal related methane emissions at no cost, according to US Deputy Climate Envoy Richard Duke. Addressing such emissions deliver invaluable co-benefits on the inside. 15% of all deaths (7million a year) are due to polluted air, according to Jane Burston of the Clean Air Fund. Companies are having to pay a pollution premium to attract talent to polluted cities.

It’s both the out and the in-side of the doughnut we need to focus on for a just transition to happen. According to Heike Henn, of Germany’s Federal Ministry for Economic Affairs and Climate Action and whatnot, Article 6 is emerging as the mechanism to allocate those $100bn/a finance pledged in Paris which never materialised as well as the trillions needed to implement NDCs (Nationally Determined Contributions) and SDGs.

Not Article 6.2 though, which requires adjustments in GHG registries upon the transfer of a carbon credits (Internationally Transferrable Mitigation Outcome – ITMO) and is already seeing emerging economies lowering ambition in their NDCs. Article 6.4 is what I’m talking about. Although it will take years to be operationalised, its infrastructure is being developed as we speak. The Climate Action Data Trust, for example, can significantly lower transaction costs of carbon market transactions through automated Measurement, Reporting and Verification (MRV) and tokenisation to create digital carbon assets.

Now it’s down to ambitious countries to form alliances and agree on a sharing mechanism to convert the 1.5C target into demand for mitigation action distributed dynamically over time, and measure achievement and contribution using Article 6.4. “Getting to net zero is a heroic task”, according to Dirk Forrister of the International Emissions Trading Association, “and you won’t get there by going alone”.

Where does this leave 1.5C? “I find it hard to stay optimistic”, said Nichola Sturgeon on day 1 of COP27. I echo this sentiment. Yet we need to remind ourselves that the combined net zero targets, if implemented, can limit warming to 1.7C and increase, yes INCREASE, global GDP by 0.4% per year, according to Fatih Birol from the IEA. If we can’t sort this out, bins will be burning.

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This blog was written by Cabot Institute for the Environment member Dr Colin Nolden, Bristol Law School, University of Bristol.

Colin Nolden