̽��ֱ�� of Cambridge - atmosphere

Researchers deal a blow to theory that Venus once had liquid water on its surface

sc604 — Mon, 02 Dec 2024 16:01:07 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, studied the chemical composition of the Venusian atmosphere and inferred that its interior is too dry today for there ever to have been enough water for oceans to exist at its surface. Instead, the planet has likely been a scorching, inhospitable world for its entire history.

̽��ֱ��results, reported in the journal Nature Astronomy, have implications for understanding Earth’s uniqueness, and for the search for life on planets outside our Solar System. While many exoplanets are Venus-like, the study suggests that astronomers should narrow their focus to exoplanets which are more like Earth.

From a distance, Venus and Earth look like siblings: it is almost identical in size and is a rocky planet like Earth. But up close, Venus is more like an evil twin: it is covered with thick clouds of sulfuric acid, and its surface has a mean temperature close to 500°C.

Despite these extreme conditions, for decades, astronomers have been investigating whether Venus once had liquid oceans capable of supporting life, or whether some mysterious form of ‘aerial’ life exists in its thick clouds now.

“We won’t know for sure whether Venus can or did support life until we send probes at the end of this decade,” said first author Tereza Constantinou, a PhD student at Cambridge’s Institute of Astronomy. “But given it likely never had oceans, it is hard to imagine Venus ever having supported Earth-like life, which requires liquid water.”

When searching for life elsewhere in our galaxy, astronomers focus on planets orbiting their host stars in the habitable zone, where temperatures are such that liquid water can exist on the planet’s surface. Venus provides a powerful limit on where this habitable zone lies around a star.

“Even though it’s the closest planet to us, Venus is important for exoplanet science, because it gives us a unique opportunity to explore a planet that evolved very differently to ours, right at the edge of the habitable zone,” said Constantinou.

There are two primary theories on how conditions on Venus may have evolved since its formation 4.6 billion years ago. ̽��ֱ��first is that conditions on the surface of Venus were once temperate enough to support liquid water, but a runaway greenhouse effect caused by widespread volcanic activity caused the planet to get hotter and hotter. ̽��ֱ��second theory is that Venus was born hot, and liquid water has never been able to condense at the surface.

“Both of those theories are based on climate models, but we wanted to take a different approach based on observations of Venus’ current atmospheric chemistry,” said Constantinou. “To keep the Venusian atmosphere stable, then any chemicals being removed from the atmosphere should also be getting restored to it, since the planet’s interior and exterior are in constant chemical communication with one another.”

̽��ֱ��researchers calculated the present destruction rate of water, carbon dioxide and carbonyl sulphide molecules in Venus’ atmosphere, which must be restored by volcanic gases to keep the atmosphere stable.

Volcanism, through its supply of gases to the atmosphere, provides a window into the interior of rocky planets like Venus. As magma rises from the mantle to the surface, it releases gases from the deeper portions of the planet.

On Earth, volcanic eruptions are mostly steam, due to our planet’s water-rich interior. But, based on the composition of the volcanic gases necessary to sustain the Venusian atmosphere, the researchers found that volcanic gases on Venus are at most six percent water. These dry eruptions suggest that Venus’s interior, the source of the magma that releases volcanic gases, is also dehydrated.

At the end of this decade, NASA’s DAVINCI mission will be able to test and confirm whether Venus has always been a dry, inhospitable planet, with a series of flybys and a probe sent to the surface. ̽��ֱ��results could help astronomers narrow their focus when searching for planets that can support life in orbit around other stars in the galaxy.

“If Venus was habitable in the past, it would mean other planets we have already found might also be habitable,” said Constantinou. “Instruments like the James Webb Space Telescope are best at studying the atmospheres of planets close to their host star, like Venus. But if Venus was never habitable, then it makes Venus-like planets elsewhere less likely candidates for habitable conditions or life.

“We would have loved to find that Venus was once a planet much closer to our own, so it’s kind of sad in a way to find out that it wasn’t, but ultimately it’s more useful to focus the search on planets that are mostly likely to be able to support life – at least life as we know it.”

̽��ֱ��research was supported in part by the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Tereza Constantinou, Oliver Shorttle, and Paul B Rimmer. ‘A dry Venusian interior constrained by atmospheric chemistry.’ Nature Astronomy (2024). DOI: 10.1038/s41550-024-02414-5

A team of astronomers has found that Venus has never been habitable, despite decades of speculation that our closest planetary neighbour was once much more like Earth than it is today.

NASA/Jet Propulsion Laboratory-Caltech

View of surface of Venus

̽��ֱ��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 – 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

Licence type:

Public Domain

Historic fires trapped in Antarctic ice yield key information for climate models

cmm201 — Fri, 09 Aug 2024 15:25:07 +0000

Researchers from the ̽��ֱ�� of Cambridge and the British Antarctic Survey tracked fire activity over the past 150 years by measuring carbon monoxide trapped in Antarctic ice. This gas is released, along with smoke and particulates, by wildfires, cooking and communal fires.

̽��ֱ��findings, reported in the Proceedings of the National Academy of Sciences, reveal that biomass burning has been more variable since the 1800s than had been thought. ̽��ֱ��new data could help improve climate models, which rely on information about past atmospheric gases, such as carbon monoxide, to improve their forecasts.

“We’ve been missing key information from the period when humans started to dramatically alter Earth’s climate; information needed to test and develop climate models,” said Rachael Rhodes, senior author of the paper from Cambridge’s Department of Earth Sciences.

̽��ֱ��new carbon monoxide record fills that gap in time. ̽��ֱ��researchers charted the strength of biomass burning between 1821 and 1995 by measuring carbon monoxide in ice cores from Antarctica. ̽��ֱ��layers of ice inside these cores formed when snow was buried under subsequent years’ snowfall, encasing pockets of air that directly sample the atmosphere's composition at the time.

“It’s rare to find trace gases trapped in ice cores for the most recent decades,” said Ivo Strawson, lead author of the study who is jointly based at Cambridge Earth Sciences and the British Antarctic Survey. “We need information on the atmosphere's composition following the onset of industrialisation to reduce uncertainties in climate models, which rely on these records to test or drive their simulations.”

A major difficulty with taking gas measurements from very young ice is that pressurised air bubbles haven’t had time to form under the weight of more snow, said Strawson. To get around this problem, the researchers studied ice from locations where snow accumulates rapidly. These ice cores, held in BAS’ dedicated Ice Core Laboratory, were collected from the Antarctic Peninsula as part of previous international projects.

To measure carbon monoxide, the researchers developed a state-of-the-art analysis method, which melts ice continuously while simultaneously extracting the air. They collected tens of thousands of gas measurements for the past 150 years.

̽��ֱ��researchers found that the strength of biomass burning has dropped steadily since the 1920s. That decline, said Rhodes, coincides with the expansion and intensification of agriculture in southern Africa, South America, and Australia during the early 20th century. With wildlands converted into farmland, forest cover was restricted and in turn fire activity dropped. “This trend reflects how land conversion and human expansion have negatively impacted landscapes and ecosystems, causing a major shift in the natural fire regime and in turn altering our planet’s carbon cycle,” said Rhodes.

One assumption made by many climate models, including those used by the IPCC, is that fire activity has increased in tandem with population growth. But, said Rhodes, “our work adds to a growing mass of evidence that this assumption is wrong, and the inventories of historic fire activity need to be corrected so that models can accurately replicate the variability we see in our record.”

Rachael Rhodes is a Fellow of Wolfson College, Cambridge.

Reference:
Ivo Strawson et al. "Preindustrial Southern Hemisphere biomass burning variability inferred from ice core carbon monoxide records." Proceedings of the National Academy of Sciences(2024). DOI: https://doi.org/10.1073/pnas.2402868121

Pollutants preserved in Antarctic ice document historic fires in the Southern Hemisphere, offering a glimpse at how humans have impacted the landscape and providing data that could help scientists understand future climate change.

̽��ֱ�� of Cambridge

Rachael Rhodes

Yes

Mysterious missing component in the clouds of Venus revealed

vb425 — Tue, 09 Jan 2024 10:05:24 +0000

What are the clouds of Venus made of? Scientists know they are mainly made of sulfuric acid droplets, with some water, chlorine, and iron. Their concentrations vary with height in the thick and hostile Venusian atmosphere. But until now they have been unable to identify the missing component that would explain the clouds’ patches and streaks, only visible in the UV range.

In a study published in Science Advances, researchers from the ̽��ֱ�� of Cambridge synthesised iron-bearing sulfate minerals that are stable under the harsh chemical conditions in the Venusian clouds. Spectroscopic analysis revealed that a combination of two minerals, rhomboclase and acid ferric sulfate, can explain the mysterious UV absorption feature on our neighbouring planet.

“ ̽��ֱ��only available data for the composition of the clouds were collected by probes and revealed strange properties of the clouds that so far we have been unable to fully explain,” said Paul Rimmer from the Cavendish Laboratory and co-author of the study. “In particular, when examined under UV light, the Venusian clouds featured a specific UV absorption pattern. What elements, compounds, or minerals are responsible for such observation?”

Formulated on the basis of Venusian atmospheric chemistry, the team synthesised several iron-bearing sulfate minerals in an aqueous geochemistry laboratory in the Department of Earth Sciences. By suspending the synthesised materials in varying concentrations of sulfuric acid and monitor the chemical and mineralogical changes, the team narrowed down the candidate minerals to rhomboclase and acid ferric sulfate, of which the spectroscopic features were examined under light sources specifically designed to mimic the spectrum of solar flares (Rimmer’s FlareLab; Cavendish Laboratory).

Researchers from Harvard ̽��ֱ�� provided measurements of the UV absorbance patterns of ferric iron under extreme acidic conditions, in an attempt to mimic the even more extreme Venusian clouds. ̽��ֱ��scientists are part of the newly-established Origins Federation, which promotes such collaborative projects.

“ ̽��ֱ��patterns and level of absorption shown by the combination of these two mineral phases are consistent with the dark UV-patches observed in Venusian clouds,” said co-author Clancy Zhijian Jiang, from the Department of Earth Sciences, Cambridge. “These targeted experiments revealed the intricate chemical network within the atmosphere, and shed light on the elemental cycling on the Venusian surface.”

“Venus is our nearest neighbour, but it remains a mystery,” said Rimmer. “We will have a chance to learn much more about this planet in the coming years with future NASA and ESA missions set to explore its atmosphere, clouds and surface. This study prepares the grounds for these future explorations.”

̽��ֱ��research was supported by the Simons Foundation, and the Origins Federation.

Reference:
Clancy Zhijian Jiang et al., ‘Iron-sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus.’ Science Advances (2024). DOI:10.1126/sciadv.adg8826

Researchers may have identified the missing component in the chemistry of the Venusian clouds that would explain their colour and 'splotchiness' in the UV range, solving a longstanding mystery.

FreelanceImages/Universal Images Group/Science Photo Library via Getty Images

Sunrise over Venus

Yes

Why do climate models underestimate polar warming? ‘Invisible clouds’ could be the answer

sc604 — Wed, 08 Nov 2023 16:06:47 +0000

̽��ֱ��Earth’s average surface temperature has increased drastically since the start of the Industrial Revolution, but the warming effect seen at the poles is even more exaggerated. While existing climate models consider the increased heating in the Arctic and Antarctic poles, they often underestimate the warming in these regions. This is especially true for climates millions of years ago, when greenhouse gas concentrations were very high.

This is a problem because future climate projections are generated with these same models: if they do not produce enough warming for the past, we might underestimate polar warming – and therefore the associated risks, such as ice sheet or permafrost melting – for the future.

“During my PhD, I was drawn to the fact that the climate models we are using do not represent the magnitude of warming that happens in the Arctic,” said lead author Dr Deepashree Dutta from Cambridge’s Department of Geography, who carried out the work during her PhD at UNSW. “At the same time, we knew that the majority of these models do not represent the upper layers of the atmosphere very well. And we thought this might be a missing link.”

̽��ֱ��team turned their focus to a key atmospheric element that is missing in most models — polar stratospheric clouds — and found that they can explain a large part of the missing warming in models.

Their results, published in the journal Nature Geoscience, show that there is still much to learn about the climate of the past, present and future.

Climate models are computer simulations of our global climate system that are built using our theoretical understanding of how the climate works. They can be used to recreate past conditions or predict future climate scenarios.

Climate models incorporate many factors that influence the climate, but they cannot include all real-world processes. One consequence of this is that generally, climate models simulate polar climate change that is smaller than actual observations.

“ ̽��ֱ��more detail you include in the model, the more resources they require to run,” said co-author Dr Martin Jucker from UNSW. “It’s often a toss-up between increasing the horizontal or vertical resolution of the model. And as we live down here at the surface of the earth, the detail closer to the surface is often prioritised.”

In 1992, American paleoclimatologist Dr Lisa Sloan first suggested that the extreme warming at high latitudes during past warm periods may have been caused by polar stratospheric clouds.

Polar stratospheric clouds form at very high altitudes (15-25 km above the Earth's surface), and at very low temperatures (over the poles). They are also called nacreous or mother-of-pearl clouds because of their bright and sometimes luminous hues, although they are not normally visible to the naked eye.

These polar stratospheric clouds have a similar effect on climate as greenhouse gases – they trap heat that would otherwise be lost to space and warm the surface of the Earth.

“These clouds form under complex conditions, which most climate models cannot reproduce. And we wondered if this inability to simulate these clouds may result in less surface warming at the poles than what we’ve observed in the real world,” said Dutta.

Thirty years after Sloan’s research, Dutta wanted to test this theory using one of the few atmospheric models that incorporates polar atmospheric clouds, to see if it might explain the disparities in warming between observational data and climate models.

“I wanted to test this theory by running an atmospheric model that includes all necessary processes with conditions that resembled a time period over 50 million years ago, known as the early Eocene. It was a period of Earth’s history when the planet was very hot and the Arctic was ice-free throughout the year,” said Dutta.

̽��ֱ��Eocene was also a period characterised by high methane content, and the position of continents and mountains was different to today.

“Climate models are far too cold in the polar regions, when simulating these past hot climates, and this has been an enigma for the past thirty years,” said Jucker. “ ̽��ֱ��early Eocene was a period in the Earth’s climate with extreme polar warming, so presented the perfect test for our climate models.”

̽��ֱ��team found that the elevated methane levels during the Eocene resulted in an increase in polar stratospheric cloud formation. They found that under certain conditions, the local surface warming due to stratospheric clouds was up to 7 degrees Celsius during the coldest winter months. This temperature difference significantly reduces the gap between climate models and temperature evidence from climate archives.

By comparing future simulations to simulations of the Eocene, the researchers also discovered that it isn’t just methane that was needed to produce polar stratospheric clouds. “This is another key finding of this work,” said Dutta. “It’s not just methane, but it's also the Earth’s continental arrangement, which plays an important role in forming these stratospheric clouds. Because if we input the same amount of methane for our future climate, we do not see the same increase in stratospheric clouds.”

̽��ֱ��research has provided some of the answers to questions about the climate of the deep past, but what does that mean for future projections?

“We found that stratospheric clouds account for the accelerated warming at the poles that is often left out of our climate models, and of course this could potentially mean that our future projections are also not warm enough,” said Jucker. “But the good news is that these clouds are more likely to form under the continental arrangement that was present tens of millions of years ago, and is not found on Earth now. Therefore, we don’t expect such large increases in stratospheric clouds in the future.”

This new research has not only helped to provide a piece of the puzzle as to why temperature recordings in the Arctic are always warmer than climate models – it has also provided new insights into the Earth’s past climate.

“Our study shows the value of increasing the detail of climate models, where we can,” said Dutta. “Although we already know a lot about these clouds theoretically, until we include them in our climate models, we won’t know the full scale of their impact.”

Reference:
Deepashree Dutta et al. ‘Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds.’ Nature Geoscience (2023). DOI: 10.1038/s41561-023-01298-w

Adapted from a UNSW press release.

Stratospheric clouds over the Arctic may explain the differences seen between the polar warming calculated by climate models and actual recordings, according to researchers from the ̽��ֱ�� of Cambridge and UNSW Sydney.

Our study shows the value of increasing the detail of climate models where we can

Deepashree Dutta

Cavan Images / Per-Andre Hoffmann via Getty Images

Mother of pearl clouds (nacreous clouds), Polar Stratospheric Clouds.

̽��ֱ��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

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

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

̽��ֱ��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

No signs (yet) of life on Venus

sc604 — Tue, 14 Jun 2022 15:00:00 +0000

Researchers from the ̽��ֱ�� of Cambridge used a combination of biochemistry and atmospheric chemistry to test the ‘life in the clouds’ hypothesis, which astronomers have speculated about for decades, and found that life cannot explain the composition of the Venusian atmosphere.

Any life form in sufficient abundance is expected to leave chemical fingerprints on a planet’s atmosphere as it consumes food and expels waste. However, the Cambridge researchers found no evidence of these fingerprints on Venus.

Even if Venus is devoid of life, the researchers say their results, reported in the journal Nature Communications, could be useful for studying the atmospheres of similar planets throughout the galaxy, and the eventual detection of life outside our Solar System.

“We’ve spent the past two years trying to explain the weird sulphur chemistry we see in the clouds of Venus,” said co-author Dr Paul Rimmer from Cambridge’s Department of Earth Sciences. “Life is pretty good at weird chemistry, so we’ve been studying whether there’s a way to make life a potential explanation for what we see.”

̽��ֱ��researchers used a combination of atmospheric and biochemical models to study the chemical reactions that are expected to occur, given the known sources of chemical energy in Venus’s atmosphere.

“We looked at the sulphur-based ‘food’ available in the Venusian atmosphere – it’s not anything you or I would want to eat, but it is the main available energy source,” said Sean Jordan from Cambridge’s Institute of Astronomy, the paper’s first author. “If that food is being consumed by life, we should see evidence of that through specific chemicals being lost and gained in the atmosphere.”

̽��ֱ��models looked at a particular feature of the Venusian atmosphere – the abundance of sulphur dioxide (SO2). On Earth, most SO2 in the atmosphere comes from volcanic emissions. On Venus, there are high levels of SO2 lower in the clouds, but it somehow gets ‘sucked out’ of the atmosphere at higher altitudes.

“If life is present, it must be affecting the atmospheric chemistry,” said co-author Dr Oliver Shorttle from Cambridge’s Department of Earth Sciences and Institute of Astronomy. “Could life be the reason that SO2 levels on Venus get reduced so much?”

̽��ֱ��models, developed by Jordan, include a list of metabolic reactions that the life forms would carry out in order to get their ‘food’, and the waste by-products. ̽��ֱ��researchers ran the model to see if the reduction in SO2 levels could be explained by these metabolic reactions.

They found that the metabolic reactions can result in a drop in SO2 levels, but only by producing other molecules in very large amounts that aren’t seen. ̽��ֱ��results set a hard limit on how much life could exist on Venus without blowing apart our understanding of how chemical reactions work in planetary atmospheres.

“If life was responsible for the SO2 levels we see on Venus, it would also break everything we know about Venus’s atmospheric chemistry,” said Jordan. “We wanted life to be a potential explanation, but when we ran the models, it isn’t a viable solution. But if life isn’t responsible for what we see on Venus, it’s still a problem to be solved – there’s lots of strange chemistry to follow up on.”

Although there’s no evidence of sulphur-eating life hiding in the clouds of Venus, the researchers say their method of analysing atmospheric signatures will be valuable when JWST, the successor to the Hubble Telescope, begins returning images of other planetary systems later this year. Some of the sulphur molecules in the current study are easy to see with JWST, so learning more about the chemical behaviour of our next-door neighbour could help scientists figure out similar planets across the galaxy.

“To understand why some planets are alive, we need to understand why other planets are dead,” said Shorttle. “If life somehow managed to sneak into the Venusian clouds, it would totally change how we search for chemical signs of life on other planets.”

“Even if ‘our’ Venus is dead, it’s possible that Venus-like planets in other systems could host life,” said Rimmer, who is also affiliated with Cambridge’s Cavendish Laboratory. “We can take what we’ve learned here and apply it to exoplanetary systems – this is just the beginning.”

̽��ֱ��research was funded by the Simons Foundation and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Sean Jordan, Oliver Shorttle and Paul B Rimmer. ‘Proposed energy-metabolisms cannot explain the atmospheric chemistry of Venus.’ Nature Communications (2022). DOI: 10.1038/s41467-022-30804-8

̽��ֱ��unusual behaviour of sulphur in Venus’ atmosphere cannot be explained by an ‘aerial’ form of extra-terrestrial life, according to a new study.

Even if ‘our’ Venus is dead, it’s possible that Venus-like planets in other systems could host life

Paul Rimmer

NASA/JPL-Caltech

Venus from Mariner 10

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Women in STEM: Dr Maria Russo

sc604 — Thu, 12 Mar 2020 06:15:05 +0000

Cambridge ̽��ֱ�� is an amazing cauldron of very talented people. I have been working in the Department of Chemistry for over ten years as a Research Scientist, funded by the National Centre for Atmospheric Science (NCAS). ̽��ֱ��Earth's atmosphere and climate are highly complex systems to study and require a multidisciplinary approach. ̽��ֱ��Cambridge Centre for Climate Science pulls together the skills and knowledge of people from different ̽��ֱ�� departments and the British Antarctic Survey to enable such a multidisciplinary approach. During my undergraduate degree at the ̽��ֱ�� of Palermo in Italy, I spent six months studying in the UK as an Erasmus exchange student. This was an inspiring experience and after completing an MPhil in Chemistry I decided to go back to the UK and pursue a PhD at UCL.

I joined the Met Office after completing my postgraduate degree and worked there as a climate scientist for a few years. However, my job was of a very technical nature and I missed the excitement of interest-led research. A key moment in my career came when I decided to leave my permanent position there to pursue my research interests. I found a very relevant job in Cambridge and decided to accept it, despite the fixed-term nature of ̽��ֱ�� employment. I'm glad I took that risk and followed my interests as this has paid off in the long-term.

My interests include atmospheric pollution in the urban environment, tropical storms and their impact on the ozone layer, and climate change. I use computer simulations to study the interplay of the physical and chemical processes that affect the Earth's atmosphere and all of its living creatures. Most of my days are spent on a computer looking at large multidimensional datasets and trying to find patterns and trends. We use computer models to simulate the atmosphere and its chemical components, so one of my jobs is to test the model results are accurate, by comparing the model output to observations from satellites.

I hope my research will lead to better understanding of the atmosphere and potentially new ways to understand the links between climate and air pollution, along with increased awareness of the damage that certain technologies could be inflicting on our planet, and in turn on our health.

If pursuing further education in science or a STEM career is what you want to do, then don't be put off by statistics or what anyone might say. There is a role and a need for more women in STEM and things are getting rapidly and noticeably better for those who follow this path. More flexible working arrangements and the definition of core hours allow women who decide to have a family (such as myself) to continue their career and achieve a reasonable work/life balance. Issues of pay gap and progression still exist but they have started to be addressed thanks to initiatives such as the Athena Swan charter.

Dr Maria Russo is a Research Associate in the Department of Chemistry, where she studies the physical and chemical processes at work in the atmosphere. Here, she tells us about the links between climate and air pollution, the excitement of 'blue-skies' research, and achieving work/life balance while raising a family.

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