September 2024 – Cabot Institute for the Environment blog

Earth’s greatest mass extinction 250 million years ago shows what happens when El Niño gets out of control – new study

Posted on September 20, 2024 by amanda.woodman-hardy

252 million years ago, there was only one supercontinent: Pangaea.
ManuMata / shutterstock

Around 252 million years ago, the world suddenly heated up. Over a geologically brief period of tens of thousands of years, 90% of species were wiped out. Even insects, which are rarely touched by such events, suffered catastrophic losses. The Permian-Triassic mass extinction, as it’s known, was the greatest of the “big five” mass extinctions in Earth’s history.

Scientists have generally blamed the mass extinction on greenhouse gases released from a vast network of volcanoes which covered much of modern day Siberia in lava. But the volcanic explanation was incomplete. In our new study, we show that an enormous El Niño weather pattern in the world’s major ocean added to climate chaos and led to extinctions spreading across the globe.

It’s easy to see why volcanoes were blamed. The onset of extinction coincides almost perfectly with the beginning of the second phase of volcanism in the region known as the Siberian Traps. This led to acid rain, oceans losing their oxygen and, most notably, temperatures beyond the tolerance levels of almost all organisms. It was the greatest episode of global warming in the past 500 million years.

The world 252 million years ago

Map of world with one big supercontinent — Alex Farnsworth

However, there were outstanding questions for proponents of this seemingly simple extinction scenario: when the tropics became too hot, why did species not just migrate to cooler, higher latitudes (as is happening today)? If warming was sudden and rapid, why did species on land die off tens of thousands of years before those in the sea?

There have also been many instances of volcanic eruptions of similar scale, and even other episodes of rapid warming, but why did none of these cause a similarly catastrophic mass extinction?

Our new study reveals that the oceans rapidly heated up all across the world’s low and mid latitudes. Normally, it gets cooler as you move away from the tropics, but not this time. It simply became too hot for life in too many places.

A world prone to extremes

Using a state-of-the-art computer program, we were able to simulate what the weather and climate was like 252 million years ago. We found that, even before the rapid warming, the world would have been prone to extremes of temperature and rainfall.

That’s a consequence of all the land at the time forming into one large supercontinent, Pangaea. This meant that the climates we see today at the centre of continents – dry, with hot summers and freezing winters – were magnified.

Pangaea was surrounded by a vast ocean, Panthalassa, the surface of which would fluctuate between warm and cool periods over the years, much like the El Niño phenomenon in the Pacific today. Yet once the mass Siberian volcanism started and carbon dioxide in the atmosphere increased, those prehistoric El Niños became more intense and lasted longer thanks to the larger Panthalassa ocean being able to store more heat.

An El Niño far stronger than anything today

chart of el nino fluctuations — Change in sea surface temperature (SST) compared to the long-term average. El Niño conditions are red, La Niña (or its prehistoric equivalent) is blue. Left = modern day pre-industrial Pacific Ocean. Centre = 252 million years ago, before the Siberian Traps volcanism. Right = at the peak of the mass extinction.
Alex Farnsworth

These El Niños had a profound impact on life on land, and kicked off a sequence of events that made the climate more and more extreme. Temperatures got hotter, especially in the tropics, and huge droughts and fires caused tropical forests to die off.

This in turn was bad news for the climate, as less carbon was stored by trees, allowing more to linger in the atmosphere, leading to further warming, and even stronger and longer El Niños.

252 million years ago, pre crisis:

Animated map of temperature 252m years ago — Before the Siberian Traps volcanism 252 million years ago, the world was slightly hotter than today. (Animation shows average monthly temperatures according to the authors’ climate model).
Alex Farnsworth

These stronger El Niños caused the extreme temperatures and droughts to push outside of the tropics towards the poles, and more vegetation died off and more carbon was released. Over tens of thousands of years, extreme temperatures spread over much of the world’s surface. Eventually, the warming began to harm life in the oceans, particularly tiny organisms at the bottom of the food chain.

…and at the peak of the extinction:

During the peak of the crisis, in a world that was already warming thanks to volcanic gases, an El Niño would boost average temperatures by a further 4°C. That’s more than three times the total warming we have caused over the past few centuries. Back then, the El Niño-charged climate would have regularly seen peak daytime temperatures on land of 60°C or more.

The future of El Niño

In recent years El Niños have caused major changes to rainfall and temperature patterns, around the Pacific and even further afield. A strong El Niño was a factor in record-breaking temperatures through 2023 and 2024.

Fortunately, such events typically only last a few years. However, on top of human-caused warming, even these smaller scale El Niños of the present day may be enough to push fragile ecosystems beyond their limit.

El Niño is predicted to become more variable as the climate changes, though we should note that the oceans are still yet to fully respond to current warming rates. At present, nobody is forecasting another mass extinction on the scale of the one 252 million years ago, but that event provides a worrying snapshot of what happens when El Niño gets out of control.

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This blog is written by Dr Alex Farnsworth, Senior Research Associate in Meteorology, University of Bristol; David Bond, Palaeoenvironmental Scientist, University of Hull, and Paul Wignall, Professor of Palaeoenvironments, University of Leeds. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Building resilience of the UK food system to weather and climate shocks

Posted on September 11, 2024 by amanda.woodman-hardy

Climate-driven changes in extreme weather events are one of the highest-risk future shocks to the UK food system, underlining the importance of preparedness across the food chain. However, the CCC’s 2023 report on adaptation progress highlighted that current climate adaptation plans and policies, and their delivery and implementation for UK food security are either insufficient or limited. Through an ongoing Met Office cross-academic partnership activity (‘SuperRAP’) working across all eight partner universities (including Bristol), Defra, the Food Standards Agency, UKRI-BBSRC and the Global Food Security Programme, a recent perspective paper, and associated online workshops and surveys in January 2023 have:

Scoped out the direct impacts of weather and climate extremes on the UK food supply chain,
Highlighted areas where weather and climate information could support resilience across time and space scales through decision making and action,
Identified key knowledge gaps,
Made recommendations for future research and funding, and
Scoped out the potential adaptation/policy responses to the direct impacts of weather and climate extremes on the food chain, and the resulting trade-offs and consequences

The potential for weather and climate information to support decision making in agricultural and food system-related activities, and improved resilience to weather and climate shocks across time and space scales. Grey background boxes represent generalised meteorological capabilities; light blue ellipses with white outlines denote potential applications. © Crown Copyright 2021, Met Office. From Falloon et al. 2022.

However, a major gap remains in understanding the changes needed to rapidly increase the delivery and implementation of climate adaptation in support of resilience in the UK food system. A workshop on this topic was held at the University of Reading’s Henley Business School on 13-14 June 2024 bringing together academics across a wide range of disciplines and presented findings back to industry and government stakeholders for their feedback and prioritisation.

The workshop aimed to consider key areas for supporting resilience and adaptation to climate change identified by the January 2023 workshop including innovation and trialling novel management and production approaches, social innovation and enabling behavioural shifts, mutual learning, and underpinning evidence gaps. The workshop was supported by a cross-sector survey on adaptation barriers and priorities.

Overarching themes identified in the workshop included the need for a strategic, system-wide, and long-term approach, underpinned by strong inter- and transdisciplinary collaboration.

Critical evidence gaps include improving understanding of:

Impacts of international dimensions and trade on UK food ingredient and packaging availability, compared to UK-sourced products – and their interactions
Impacts of climate extremes on production and transport and effective adaptation options
Impacts of climate shocks on UK livelihood systems, households and consumers
Broader adaptation and transformation needed to escape existing ‘doom loops’
Application of tech solutions (e.g. GM/gene editing) for climate resilience and adaptation

Other issues raised included thresholds for change, land pressures, substitutability of different foods, impacts of government policy, nutrition, regenerative practices, and interactions with the energy sector.

Recommended ways forward include:

Tools, models, and methods that consider risks across the food chain and system outcomes
A focus on inter- and trans-disciplinary approaches.
Increased international collaboration/cooperation, and stronger government-science interactions
Enhancing food chain data access, use and integration, and a supportive enabling environment
Long-term trials: to provide evidence of impacts of alternative practices
Preparing the transport network for climate extremes.
A refresh of the National Food Strategy, building on latest science
A new funding landscape: long-term, strategic, visionary, systemic, trans- and interdisciplinary, co-designed and coordinated.

Other issues raised included: sharing responsibility and joined-up, transparent approaches across sectors and institutions; risk mitigation tools; use cases and roadmaps; welfare responses; interdisciplinary skills training; and research across a wider range of crops.

We are aiming to produce a peer-reviewed perspective paper on critical research (and practice) gaps, and recommendations for the way forward.

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This blog was written by Professor Pete Falloon from the Cabot Institute for the Environment and Met Office.

A bald headed man smiling with dark rimmed glasses. — Professor Pete Falloon

Chemical industry failing to stop emissions of super-strong greenhouse gas HFC-23 – new research

Posted on September 4, 2024September 4, 2024 by amanda.woodman-hardy

The potent greenhouse gas HFC-23 is emitted from the industrial production of fluoroplastics and specific refrigerants.
Quality Stock Arts/Shutterstock

Emissions of a super-strong greenhouse gas could be substantially reduced if factories would properly implement existing “destruction technology” in certain industrial production processes. If operated properly, emissions of this greenhouse gas could be cut by at least 85% – that’s equivalent to 17% of carbon dioxide emissions from global aviation.

Our research, published today in the journal Nature, scrutinises emissions of one of the most potent hydrofluorocarbon (HFC) greenhouse gases, called trifluoromethane (HFC-23). One gram of HFC-23 in the atmosphere contributes as much to the greenhouse effect as 12kg of carbon dioxide.

This unwanted byproduct comes from the production of certain gases used as refrigerants and the manufacture of fluoropolymers (a class of plastic chemicals) such as polytetrafluoroethylene (PTFE), a key ingredient in most non-stick cookware.

black frying pan, single friend egg, dark background. — Fluoroplastics are used in the production of non-stick cookware.
J.Thasit/Shutterstock

More than 150 countries have pledged to significantly reduce their HFC-23 emissions as part of the 2016 Kigali Amendment to an international treaty called the Montreal Protocol on substances that deplete the ozone layer. The breakdown of HFCs in the atmosphere does not directly link to ozone depletion, but HFCs were introduced to replace ozone-depleting substances such as chloroflourocarbons (CFCs), so they have been included in this regulation.

HFCs are also strong greenhouse gases. While the Kigali Amendment aims to reduce emissions of widely used HFCs, an exceptional arrangement is made for HFC-23. Because HFC-23 is largely emitted from production processes and not from end-use applications, its destruction as a by-product is required “to the extent practicable” as of 2020 – that means as much as possible, but it’s a vague limit.

Even before 2020, many countries, including the biggest manufacturers of PTFE such as China, reported they had installed destruction technologies at PTFE factories and are successfully destroying HFC-23. In 2020, the reported global annual emissions of HFC-23 were only around 2,000 metric tonnes – but actual global emissions, derived from atmospheric measurements, amounted to around 16,000 metric tonnes.

To unravel this discrepancy between real and reported emissions, we analysed HFC-23 emissions from a major European PTFE factory in the Netherlands, which already operates destruction technologies – these include the incineration of harmful byproducts.

The aim of our experiment was to define what “practicable” actually means, and to identify how much HFC-23 can be easily destroyed by existing technology at a factory-wide scale, considering that emissions come from both the chimneys and leaks from other parts of the plant.

With the factory’s collaboration and the consent of the Dutch environment authorities, we released a controlled amount of a tracer gas directly next to the factory: this is a non-toxic, degradable gas that does not occur in the atmosphere. We then measured the concentrations of HFC-23, other byproducts of flouropolymer manufacture, and the released tracer at an observing site run by the Europe-wide greenhouse gas research centre, the Integrated Carbon Observation System, near the Dutch village of Cabauw.

This 213m-tall tower is located around 25km away from the factory. We knew exactly how much tracer we had released and how much of it arrived at the measuring point, so we could calculate the emissions of HFC-23 and other gases.

aerial shot of tall metal tower, green fields — Measurements of HFC-23 and the tracer were carried out at the 213m Cabauw measuring mast, operated by the Royal Netherlands Meteorological Institute.
ICOS RI/Tom Oudijk, Sander Karsen, Dennis Manda, CC BY-NC-ND

Results showed that even though our estimated emissions were higher than those reported by the factory, the technology at this particular factory was working properly and successfully destroying HFC-23.

Upscaling to global emissions

However, as the industrial manufacture of fluoropolymers is currently the major known source of HFC-23 to the atmosphere, we suspect that destruction technologies are not as effectively operated as reported by manufacturers.

Our findings indicate that if all factories globally were controlling emissions in the same way as the Dutch site, HFC-23 emissions could be cut by at least around 85%, representing emissions equivalent to 170 million metric tonnes of carbon dioxide per year. This reduction equates to almost one-fifth (17%) of carbon dioxide emissions generated by all aviation traffic.

Real and reported emissions of HFC-23

An independent auditing framework for fluoropolymer production would ensure that HFC-23 is destroyed properly at factories around the world. Targeted monitoring of greenhouse gas emissions resulting from the production of fluorochemicals would further the understanding of emission sources and ensure that countries are fully compliant under different international climate and environment agreements.

Our results show that destruction technologies can effectively be implemented – in this case, at factories producing fluoropolymers such as PTFE, to significantly reduce the emissions of a highly potent greenhouse gas.

This blog is written by Dr Dominique Rust, Research Associate, School of Chemistry, University of Bristol; Dr Kieran Stanley, Senior Research Fellow, School of Chemistry, University of Bristol, and Stephen Henne, Senior Scientist, Group Atmospheric Modelling and Remote Sensing, Swiss Federal Institute of Technology Zurich. This article is republished from The Conversation under a Creative Commons license. Read the original article.