̽��ֱ�� of Cambridge - Natural Environment Research Council (NERC)

Conservation efforts are bringing species back from the brink

sc604 — Tue, 18 Mar 2025 18:30:46 +0000

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

Antarctic ice shelves hold twice as much meltwater as previously thought

sc604 — Thu, 27 Jun 2024 08:56:09 +0000

Slush – water-soaked snow – makes up more than half of all meltwater on the Antarctic ice shelves during the height of summer, yet is poorly accounted for in regional climate models.

Spanish butterflies better at regulating their body temperature than their British cousins

sc604 — Tue, 09 Jan 2024 04:32:22 +0000

Butterfly populations in northern Spain are better than their UK counterparts at regulating their body temperature, but rising global temperatures may put Spanish butterflies at greater risk of extinction.

Effect of volcanic eruptions significantly underestimated in climate projections

sc604 — Fri, 23 Jun 2023 10:49:47 +0000

While this effect is far from enough to offset the effects of global temperature rise caused by human activity, the researchers, led by the ̽��ֱ�� of Cambridge, say that small-magnitude eruptions are responsible for as much as half of all the sulphur gases emitted into the upper atmosphere by volcanoes.

̽��ֱ��results, reported in the journal Geophysical Research Letters, suggest that improving the representation of volcanic eruptions of all magnitudes will in turn make climate projections more robust.

Where and when a volcano erupts is not something that humans can control, but volcanoes do play an important role in the global climate system. When volcanoes erupt, they can spew sulphur gases into the upper atmosphere, which forms tiny particles called aerosols that reflect sunlight back into space. For very large eruptions, such as Mount Pinatubo in 1991, the volume of volcanic aerosols is so large that it single-handedly causes global temperatures to drop.

However, these large eruptions only happen a handful of times per century – most small-magnitude eruptions happen every year or two.

“Compared with the greenhouse gases emitted by human activity, the effect that volcanoes have on the global climate is relatively minor, but it’s important that we include them in climate models, in order to accurately assess temperature changes in future,” said first author May Chim, a PhD candidate in the Yusuf Hamied Department of Chemistry.

Standard climate projections, such as the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, assume that explosive volcanic activity over 2015–2100 will be at the same level as the 1850–2014 period, and overlook the effects of small-magnitude eruptions.

“These projections mostly rely on ice cores to estimate how volcanoes might affect the climate, but smaller eruptions are too small to be detected in ice-core records,” said Chim. “We wanted to make a better use of satellite data to fill the gap and account for eruptions of all magnitudes.”

Using the latest ice-core and satellite records, Chim and her colleagues from the ̽��ֱ�� of Exeter, the German Aerospace Center (DLR), the Ludwig-Maximilians ̽��ֱ�� of Munich, Durham ̽��ֱ��, and the UK Met Office, generated 1000 different scenarios of future volcanic activity. They selected scenarios representing lower, median and high levels of volcanic activity, and then performed climate simulations using the UK Earth System Model.

Their simulations show that the impacts of volcanic eruptions on climate, including global surface temperature, sea level and sea ice extent, are underestimated because current climate projections largely underestimate the plausible future level of volcanic activity.

For the median future scenario, they found that the effect of volcanoes on the atmosphere, known as volcanic forcing, is being underestimated in climate projections by as much as 50%, due in large part to the effect of small-magnitude eruptions.

“We found that not only is volcanic forcing being underestimated, but small-magnitude eruptions are actually responsible for as much as half of all volcanic forcing,” said Chim. “These small-magnitude eruptions may not have a measurable effect individually, but collectively, their effect is significant.

“I was surprised to see just how important these small-magnitude eruptions are – we knew they had an effect, but we didn’t know it was so large.”

Although the cooling effect of volcanoes is being underestimated in climate projections, the researchers stress that it does not compare with human-generated carbon emissions.

“Volcanic aerosols in the upper atmosphere typically stay in the atmosphere for a year or two, whereas carbon dioxide stays in the atmosphere for much, much longer,” said Chim. “Even if we had a period of extraordinarily high volcanic activity, our simulations show that it wouldn’t be enough to stop global warming. It’s like a passing cloud on a hot, sunny day: the cooling effect is only temporary.”

̽��ֱ��researchers say that fully accounting for the effect of volcanoes can help make climate projections more robust. They are now using their simulations to investigate whether future volcanic activity could threaten the recovery of the Antarctic ozone hole, and in turn, maintain relatively high levels of harmful ultraviolet radiation at the Earth’s surface.

̽��ֱ��research was supported in part by the Croucher Foundation and ̽��ֱ��Cambridge Commonwealth, European & International Trust, the European Union, and the Natural Environment Research Council (NERC), part of UK Research and Innovation (UKRI).

Reference:
Man Mei Chim et al. ‘Climate Projections Very Likely Underestimate Future Volcanic Forcing and Its Climatic Effects.’ Geophysical Research Letters (2023). DOI: 10.1029/2023GL103743

Researchers have found that the cooling effect that volcanic eruptions have on Earth's surface temperature is likely underestimated by a factor of two, and potentially as much as a factor of four, in standard climate projections.

These small-magnitude eruptions may not have a measurable effect individually, but collectively, their effect is significant.

May Chim

Andreas Weibel via Getty Images

Volcano erupting near El Paso, La Palma, Spain

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Giant underwater waves affect the ocean’s ability to store carbon

sc604 — Thu, 16 Mar 2023 15:00:53 +0000

An international team of researchers, led by the ̽��ֱ�� of Cambridge, the ̽��ֱ�� of Oxford, and the ̽��ֱ�� of California San Diego, quantified the effect of these waves and other forms of underwater turbulence in the Atlantic Ocean and found that their importance is not being accurately reflected in the climate models that inform government policy.

Most of the heat and carbon emitted by human activity is absorbed by the ocean, but how much it can absorb is dependent on turbulence in the ocean’s interior, as heat and carbon are either pushed deep into the ocean or pulled toward the surface.

While these underwater waves are already well-known, their importance in heat and carbon transport is not fully understood.

̽��ֱ��results, reported in the journal AGU Advances, show that turbulence in the interior of oceans is more important for the transport of carbon and heat on a global scale than had been previously imagined.

Ocean circulation carries warm waters from the tropics to the North Atlantic, where they cool, sink, and return southwards in the deep ocean, like a giant conveyer belt. ̽��ֱ��Atlantic branch of this circulation pattern, called the Atlantic Meridional Overturning Circulation (AMOC), plays a key role in regulating global heat and carbon budgets. Ocean circulation redistributes heat to the polar regions, where it melts ice, and carbon to the deep ocean, where it can be stored for thousands of years.

“If you were to take a picture of the ocean interior, you would see a lot of complex dynamics at work,” said first author Dr Laura Cimoli from Cambridge’s Department of Applied Mathematics and Theoretical Physics. “Beneath the surface of the water, there are jets, currents, and waves – in the deep ocean, these waves can be up to 500 metres high, but they break just like a wave on a beach.”

“ ̽��ֱ��Atlantic Ocean is special in how it affects the global climate,” said co-author Dr Ali Mashayek from Cambridge’s Department of Earth Sciences. “It has a strong pole-to-pole circulation from its upper reaches to the deep ocean. ̽��ֱ��water also moves faster at the surface than it does in the deep ocean.”

Over the past several decades, researchers have been investigating whether the AMOC may be a factor in why the Arctic has lost so much ice cover, while some Antarctic ice sheets are growing. One possible explanation for this phenomenon is that heat absorbed by the ocean in the North Atlantic takes several hundred years to reach the Antarctic.

Now, using a combination of remote sensing, ship-based measurements and data from autonomous floats, the Cambridge-led researchers have found that heat from the North Atlantic can reach the Antarctic much faster than previously thought. In addition, turbulence within the ocean – in particular large underwater waves – plays an important role in the climate.

Like a giant cake, the ocean is made up of different layers, with colder, denser water at the bottom, and warmer, lighter water at the top. Most heat and carbon transport within the ocean happens within a particular layer, but heat and carbon can also move between density layers, bringing deep waters back to the surface.

̽��ֱ��researchers found that the movement of heat and carbon between layers is facilitated by small-scale turbulence, a phenomenon not fully represented in climate models.

Estimates of mixing from different observational platforms showed evidence of small-scale turbulence in the upper branch of circulation, in agreement with theoretical predictions of oceanic internal waves. ̽��ֱ��different estimates showed that turbulence mostly affects the class of density layers associated with the core of the deep waters moving southward from the North Atlantic to the Southern Ocean. This means that the heat and carbon carried by these water masses have a high chance of being moved across different density levels.

“Climate models do account for turbulence, but mostly in how it affects ocean circulation,” said Cimoli. “But we’ve found that turbulence is vital in its own right, and plays a key role in how much carbon and heat gets absorbed by the ocean, and where it gets stored.”

“Many climate models have an overly simplistic representation of the role of micro-scale turbulence, but we’ve shown it’s significant and should be treated with more care,” said Mashayek. “For example, turbulence and its role in ocean circulation exerts a control over how much anthropogenic heat reaches the Antarctic Ice Sheet, and the timescale on which that happens.”

̽��ֱ��research suggests an urgent need for the instalment of turbulence sensors on global observational arrays and a more accurate representation of small-scale turbulence in climate models, to enable scientists to make more accurate projections of the future effects of climate change.

̽��ֱ��research was supported in part by the Natural Environment Research Council (NERC), part of UK Research and Innovation (UKRI).

Reference:
Laura Cimoli et al. ‘Significance of Diapycnal Mixing Within the Atlantic Meridional Overturning Circulation.’ AGU Advances (2023). DOI: 10.1029/2022AV000800

Underwater waves deep below the ocean’s surface – some as tall as 500 metres – play an important role in how the ocean stores heat and carbon, according to new research.

Turbulence plays a key role in how much carbon and heat gets absorbed by the ocean, and where it gets stored

Laura Cimoli

Laura Cimoli/GLODAP

Map of depth-integrated anthropogenic carbon

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Runaway West Antarctic ice retreat can be slowed by climate-driven changes in ocean temperature

sc604 — Mon, 16 Jan 2023 09:45:30 +0000

New research finds that ice-sheet-wide collapse in West Antarctica isn’t inevitable: the pace of ice loss varies according to regional differences in atmosphere and ocean circulation.

Seasonal change in Antarctic ice sheet movement observed for first time

sc604 — Thu, 06 Oct 2022 11:40:23 +0000

Some estimates of Antarctica’s total contribution to sea-level rise may be over- or underestimated, after researchers detected a previously unknown source of ice loss variability.

Scientists develop new method to assess ozone layer recovery

sc604 — Wed, 24 Aug 2022 14:58:39 +0000

Published in the journal Nature, their method - the Integrated Ozone Depletion (IOD) metric - provides a useful tool for policymakers and scientists.

̽��ֱ��IOD has been designed to provide a straightforward way to measure the effects of unregulated emissions of substances that deplete the ozone layer, and evaluate how effective ozone layer protection measures are.

̽��ֱ��ozone layer is found in a region of the earth’s atmosphere known as the stratosphere, and acts as an important protection barrier against most of the sun’s harmful ultraviolet rays.

Ozone-depleting gases such as chlorofluorocarbons, better known as CFCs, have been phased out under the Montreal Protocol - an international treaty agreed to protect the ozone layer.

̽��ֱ��Montreal Protocol has been largely successful, but illegal breaches are jeopardising its efficacy.

̽��ֱ��IOD indicates the impact of any new emissions on the ozone layer by considering three things: the strength of the emission, how long it will remain in the atmosphere, and how much ozone is chemically destroyed by it.

For environmental protection and human health policies, the IOD represents a simple means of calculating the impact of any given emission scenario on ozone recovery.

This new metric has been developed by researchers at the National Centre for Atmospheric Science at the ̽��ֱ�� of Cambridge and the National Centre for Earth Observation at the ̽��ֱ�� of Leeds.

Professor John Pyle, from the National Centre for Atmospheric Science and the ̽��ֱ�� of Cambridge, has dedicated his career to studying the depletion of ozone in the stratosphere and helping develop the Montreal Protocol. He is the lead author of the current Nature paper.

“Following the Montreal Protocol, we are now in a new phase - assessing the recovery of the ozone layer,” said Pyle, from Cambridge’s Yusuf Hamied Department of Chemistry. “This new phase calls for new metrics, like the Integrated Ozone Depletion - which we refer to as the IOD. Our new metric can measure the impact of emissions - regardless of their size. Using an atmospheric chemistry computer model, we have been able to demonstrate a simple linear relationship between the IOD, the size of the emissions and the chemical lifetimes. So, with knowledge of the lifetimes, it is a simple matter to calculate the IOD, making this an excellent metric both for science and policy.”

“ ̽��ֱ��Montreal Protocol is successfully protecting the ozone layer, but there is increasing evidence to suggest the ozone hole is recovering slower than expected. ̽��ֱ��IOD will be very useful for monitoring ozone recovery, and especially relevant to regulators who need to phase out substances with the potential to chemically destroy ozone.”

̽��ֱ��IOD metric has been created using a computer model of the atmosphere, called the UK Chemistry and Aerosols model (UKCA). ̽��ֱ��National Centre for Atmospheric Science and the Met Office developed the UKCA model to calculate future projections of important chemicals, such as ozone in the stratosphere.

“We have used the UKCA model to develop the IOD metric, which will enable us to estimate the effect of any new illegal or unregulated emissions on the ozone layer. In the UKCA model we can perform experiments with different types and concentrations of CFCs, and other ozone-depleting substances,” said co-author Dr Luke Abraham, also from the ̽��ֱ�� of Cambridge. “We can estimate how chemicals in the atmosphere will change in the future, and assess their impact on the ozone layer over the coming century.”

̽��ֱ��research was supported in part by the Natural Environment Research Council (NERC), part of UK Research and Innovation (UKRI).

Reference:
John A Pyle et al. ‘Integrated ozone depletion as a metric for ozone recovery.’ Nature (2022). DOI: 10.1038/s41586-022-04968-8

Adapted from a press release by the National Centre for Atmospheric Science.

Researchers have developed a new method for assessing the impacts of ozone-destroying substances that threaten the recovery of the ozone layer.

̽��ֱ��Montreal Protocol is successfully protecting the ozone layer, but there is increasing evidence to suggest the ozone hole is recovering slower than expected

John Pyle

Grant Faint via Getty Images

View of Earth from 40,000 feet

Yes