Category: Climate Change Impacts

Hunger threat as tropical fish seek cooler waters

Hunger threat as tropical fish seek cooler waters

By Paul Brown

Stocks of tropical fish that have provided vital protein for local people for generations may soon disappear as the oceans warm, leaving empty seas in their wake, scientists believe. But there could be help in international protection schemes.

Already researchers have found that fish are voting with their fins by diving deeper or migrating away from equatorial seas to find cooler waters. But now they have calculated, in a study published in the journal Nature, that tropical countries stand to lose most if not all of their fish stocks, with few if any species moving in to replace them.

Although scientists have known that the composition of stocks is changing in many world fisheries, they have not until now fully appreciated the devastating effect the climate crisis will have on tropical countries.

In the North Sea, for example, when fish like cod move north to find cooler and more congenial conditions for breeding, they are replaced by fish from further south which also have a commercial value, such as Mediterranean species like red mullet. But when fish move from the tropics there are no species from nearer the equator that are acclimatised to the hotter water and able to take their place.

Now Jorge García Molinos of Hokkaido University and colleagues in Japan and the US have undertaaken a comprehensive study of 779 commercial fish species to see how they would expand or contract their range under both moderate and more severe global warming between 2015 and 2100, using 2012 as a baseline for their distribution.

“The exit of many fishery stocks from these climate change-vulnerable nations is inevitable, but carefully designed international cooperation could significantly ease the impact on those nations”

The computer model they used showed that under moderate ocean warming tropical countries would lose 15% of their fish species by the end of this century. But if higher greenhouse gas emissions continued, fuelling more severe heat, that would rise to 40%.

The worst-affected countries would be along the north-west African seaboard, while south-east Asia, the Caribbean and Central America would also experience steep declines.

Alarmed by their findings, because of the effect they would have on the nutrition of the people who relied on fish protein for their survival, the scientists examined existing fisheries agreements to see if they took into account the fact that stocks might move because of climate change.

Analysis of 127 publicly-available international agreements showed that none contained language to deal with climate change or stock movements to other waters.

Some dealt with short-term stock fluctuations but not permanent movements, and did not deal with the possible over-fishing of replacement stocks.

Global help

The scientists suggest an urgent look at the issue at the annual UN climate talks because of the loss of fish stocks and the financial damage that warming seas will do to the economies of some of the world’s poorest countries.

They go further, suggesting that poor countries could apply for compensation for damage to their fisheries during negotiations under the Warsaw International Mechanism for Loss and Damage associated with Climate Change Impacts (WIM), and also raise the possibility of help from the Green Climate Fund, set up to help the poorest countries adapt to and mitigate the effects of climate change.

Professor García Molinos, based at Hokkaido’s Arctic Research Center,  said: “The exit of many fishery stocks from these climate-change vulnerable nations is inevitable, but carefully designed international cooperation together with the strictest enforcement of ambitious reductions of greenhouse gas emissions, especially by the highest-emitter countries, could significantly ease the impact on those nations.”

While the research relies on computer models to see how fish will react to warming seas in the future, the scientific evidence available shows that they are already responding. It also shows that keeping the world temperature increase down to 1.5°C, the preferred maximum agreed at the 2015 Paris climate talks, would help fisheries globally.

And the Hokkaido research demonstrates yet again how it is the poorest nations, which have contributed least to the carbon dioxide and other greenhouse gas emissions causing climate change, that will suffer most from their effects.

This article was originally published on the Climate News Network.
Cover photo by jean wimmerlin on Unsplash
The under-appreciated influence of the tropics on the ‘jet stream’

The under-appreciated influence of the tropics on the ‘jet stream’

By Prof Tim Woollings

Over the past decade or so, a scientific debate has emerged around whether rapid Arctic warming could be affecting extreme weather in the mid-latitudes. Much of this work focuses on the jet stream – the narrow current of strong winds encircling the globe around 40-50 degrees North.

The science is far from settled. The jet stream can vary wildly from week to week, or from year to year, and questions remain over whether any signal from the Arctic can yet be seen over the background “noise” of natural variability. (The latest study on the topic, for example, suggests the link is “insignificant”.)

The current winter provides an interesting, if trivial, example. In the Arctic, the steady decline of sea ice continues, with the January 2020 average extent among the lowest 10 years in the satellite record. According to some of the most widely reported theories, we might expect the jet to have been weaker and more “wavy” this winter as a result. But the reality is quite the opposite. So far this season, the jet has mostly been strong and straight, bringing mild and stormy weather to much of northern Europe.

Of course, lots of this is just ‘weather’ – we expect a certain randomness in the jet stream – and this is a key reason why influences, such as Arctic warming, are so hard to pin down. But, intriguingly, the jet this winter seems to have been highly predictable, with early warnings of such a pattern first being made in the autumn. 

We cannot say for certain what has caused this yet, but most meteorological eyes are directed away from the Arctic, towards the south. And, in fact, there is possibly an even more important influence on our weather under a changing climate: the tropics.


Ultimately, the jet stream derives its energy from the contrast in temperatures between the warm air over the equator and the cold conditions of the Arctic. And is it intimately tied to conditions in the tropics. 

Blessed with a surplus of energy pouring in from the sun, the tropics are in many ways the powerhouse of the Earth’s climate. Somewhere near the equator, depending on season, the surface will face directly towards the sun and so the air here will be heated more than anywhere else, becoming lighter and rising upwards as a result. This forms a giant convection cell in the atmosphere, known as the Hadley cell, with air rising above the equator before moving away, to both the north and south, and then sinking again.

Global circulation of Earth's atmosphere displaying Hadley cell, Ferrell cell and polar cell. Credit: Kaidor, published under CC BY-SA 3.0
Global circulation of Earth’s atmosphere displaying Hadley cell, Ferrell cell and polar cell. Credit: Kaidor, published under CC BY-SA 3.0

George Hadley was a London lawyer, pondering science questions in his spare time, when he hit upon the basic mechanism explaining the “trade winds”. These are the year-round east-to-west winds that blow across the tropics, on which traders sailing across the Atlantic relied for a swift passage to the Americas. Hadley described the theory in his seminal paper, published by the Royal Society in 1735.

Hadley, G. (1735) VI. Concerning the cause of the general trade-winds, Philosophical Transactions, doi:10.1098/rstl.1735.0014
Hadley, G. (1735) VI. Concerning the cause of the general trade-winds, Philosophical Transactions, doi:10.1098/rstl.1735.0014

Hadley first theorised the existence of the cell which now bears his name and also that the near-surface air moving towards the equator would be turned by the rotation of the Earth, forming the trade winds. He also predicted that, on the flip side of his cell, there should be strong winds blowing from west to east far above the surface, which he named the “anti-trades”. Today, of course, we call this the jet stream.

(Cartoons of the atmosphere typically feature two jets, one linked to the Hadley cell and one further north linked to a much weaker feature called the polar cell. Although this picture is useful, the two jets are, in reality, often merged into one dominant structure in the mid-latitudes, simply referred to as the jet stream.)

Tropical changes

While scientists are still pondering how variations in the Arctic may affect the jet, the influence of the tropics is abundantly clear. 

We need look no further than the dramatic weather disruption caused by El Niño events in the Pacific Ocean, when the balance between the tropical trade winds and the warm equatorial ocean currents is upset. By shifting the locations of the powerful convection driving the Hadley cell, these events send “waves” along the jet stream that can temporarily alter weather patterns around much of the world.

El Niño is a naturally-occuring phenomenon affecting weather and climate worldwide.

Normally, trade winds blow strongly from east to west in the tropical Pacific. During an El Niño, the trade winds relax, cutting off the supply of cool water to the sea surface.
Infographic: What is El Nino? Credit: Tom Prater and Rosamund Pearce/Carbon Brief.

El Niño is the poster-child of climate variability, responsible for much of the skill in our long-range “seasonal” forecasts, which aim to predict average conditions for the season ahead. But there is more to the tropics than just El Niño. The tropical atmosphere is much less stable than that over the Arctic, enabling powerful storm systems to reach up and shunt around air masses up at the heights where the jet is strongest.

For example, it seems likely that weather patterns in the tropics have helped to nudge the jet into its strong and straight configuration this winter, and it is this signal which enabled early warnings for Europe in the autumn of 2019. Specifically, this year’s events are quite consistent with some previous studies of the influence of Indian Ocean weather patterns on the jet stream. 

And what about climate change? Might we be seeing changes in the jet stream already because of how the tropics are responding to warming? 

The tropics are indeed changing, although there is more uncertainty over how exactly than there is in the Arctic. For example, George Hadley’s great circulation cell has been expanding over recent decades, its boundaries inching slightly, but detectably, polewards. 

While this is exactly the signal we expect to arise from climate change, our best assessment is currently that much of the recent changes reflect natural variations, at least in the northern hemisphere. (In the southern hemisphere, the climate change signal is clearer, especially as it is boosted by the effects of stratospheric ozone depletion.)

Ocean heat

The tropical oceans are, of course, warming, along with most oceans around the world. However, here again there is uncertainty over exactly how. 

Climate models generally predict the tropical Pacific will warm most strongly in the east, close to South America, while the observed trends show strongest warming instead in the west. Given the sensitivity to these regions evidenced by El Niño, this discrepancy has serious implications for our ability to predict the details of changing weather patterns. 

Surface temperature anomalies for 2019 from Berkeley Earth, using a 1951-80 baseline.
Surface temperature anomalies for 2019 from Berkeley Earth, using a 1951-80 baseline.

Some new evidence suggests that the observed pattern of stronger western warming might be a signature of climate change, regardless of what the models say. Given the extent to which the details really matter in the tropical Pacific, however, uncertainty is likely to remain here for some time.

Keeping this uncertainty in mind, though, has the warming of the tropical oceans had any effect on the jet stream yet? 

Some of our recent work suggests, potentially, yes. El Niño peaks in the northern hemisphere winter – it was originally named after the infant Jesus by Peruvian fishermen – but it also has important impacts in summer by sending giant, continent-sized waves along the jet stream. 

For example, a series of extreme weather events rocked Eurasia in 2010, from the searing Russian heatwave to the torrential Pakistan floods, and it seems the climate dice were loaded for these events by La Niña, the so-called “little sister” to El Niño.

Crucially, the pathway for these influences seems to have shifted and strengthened in recent decades, due to a subtle shift of the jet, so that El Niño and La Niña now affect parts of Eurasia in summer that they did not reach before. This is associated with a subtle southward shift of the jet over southeast Asia, which makes it more sensitive to weather disturbances from over the Pacific.

We have been able to reproduce this change in climate model experiments but – importantly – this occurs only when the observed warming of the tropical oceans and the subsequent influence on the jet is included.

It is early days for this type of research, and many uncertainties remain, but we might just be starting to see an example of how the tropics will affect jet stream variability under climate change. 

In any case, both Hadley’s circulation cell and El Niño’s shockwaves demonstrate the power of the tropics over the jet stream. As weather patterns alter in our warming world, those of us in the northern mid-latitudes should be looking nervously to the south at least as much as to the north.

This article was originally posted on The Carbon Brief under CC licensing.
Cover photo by NASA Johnson on Flickr.
Dark Ice on the World’s Glaciers

Dark Ice on the World’s Glaciers

By Nathan Chrismas

This article was originally published at the outdoor community climate change charity Protect Our Winters UK.

Dr. Nathan Chrismas is a climber and scientist studying ecological genomics. In this article he explains the causes and implications of dark glaciers. 

Dark glaciers are increasingly common because of climate change and cause glaciers to melt more quickly. There’s a surprising new culprit being discovered…

When I was at school, during the 1990s, our class was given a maths test. One of the questions asked was “What is the probability of seeing a white bus?” To our maths teacher, the answer was simple. Buses were red and the probability of seeing a white bus was zero. Any other response was the sign of a child with either a) severe visual impairment or b) a complete failure to grasp what probability actually was. Unknown to her, our town had just introduced a Park and Ride scheme making use of, you guessed it, white buses. 

After scratching my head for a while I decided that, while there were not that many white buses, there were definitely more than none. I settled on 1 in 10. While my answer was met with ridicule, it simply reflected changing facts in a changing environment. 

Grey rubble strewn surface of a glacier. Photo by Martin Adams on Unsplash

A similar question on a different Year 7 maths test might have gone like this: “What is the probability of seeing a black glacier?” Twenty-five years ago, the answer might have seemed equally as cut and dried but even then the answer was not that simple and our understanding since then has increased rapidly.

Today our expectation of glaciers as a shining white sea of ice is all too often met with a grey, rubble strewn reality. The rocks and dust on glacier surfaces are a striking symptom of our changing climate. 

The melting of permafrost high in the mountains means that once solid terrain is crumbling onto the glaciers below. Soot, or black carbon, from wildfires, burning fossil fuels in coal fired power plants and in the petrol and diesel engines of vehicles, can also be deposited on the surface of glaciers adding to the inorganic components and darkening the ice. Black carbon is itself a huge issue as it causes a second problem. It lingers in the air, causing the earth to absorb more of the sun’s energy.

However in the past few years, research has revealed a new part of the story when it comes to darkening glaciers: algae.

Ice algae are an essential component of the world’s frozen ecosystems. These microscopic photosynthetic organisms are fantastic examples of evolutionary adaptation. They possess many features that allow them to grow on the snow and ice where other organisms would fail to survive. Their dark colours are the result of pigments that protect them from the bright sunlight experienced high in the mountains and the polar regions.

Yet, they have a darker side. The dark colours of the algae reduce the overall reflectivity of glacier surfaces. The scientific term for reflectivity is albedo, and lower albedo leads to increased absorbance of heat from the sun. With that heat comes melting. Imagine the difference between sweating it out in a black t-shirt on a hot day compared to the relative cool of a white t-shirt. 

This process is ongoing, to some extent, on glaciers all over the world. It is particularly obvious in Greenland. Here, great swathes of the ice sheet on the west of the country darken with algal blooms every year. This darkening has the potential to accelerate surface melt (melt that is already rapid because of rising temperatures). 

Algae covered ice on the Greenland Ice Sheet near Kangerlussuaq. Picture Source: Google Earth.

This in turn promotes an environment for more algae to bloom, further increasing melt. Over an area the size of Greenland, the contribution that this bio albedofeedback of blooming algae and melting ice might make to global sea level rise is massive, with potentially dire consequences for coastal communities worldwide.

Whether it is because of algae, soot, or rocks, it is becoming increasingly obvious that the probability of finding a white glacier untouched by climate change is vanishingly small. The implications for the environment and global community are huge. Let us not leave what happens next to chance. #winterneedsus

Cover photo by Vince Gx on Unsplash

Rising tides will leave no choice for US millions

Rising tides will leave no choice for US millions

By Tim Radford

The Texan city of Houston is about to grow in unexpected ways, thanks to the rising tides. So will Dallas. Real estate agents in Atlanta, Georgia; Denver, Colorado; and Las Vegas, Nevada could expect to do roaring business.

The inland counties around Los Angeles, and close to New Orleans in Louisiana, will suddenly get a little more crowded. And from Boston in the north-east to the tip of Florida, Americans will be on the move.

That is because an estimated 13 million US citizens could some time in this century become climate refugees, driven from their seaside homes by sea level rise of possibly 1.8 metres, according to new research.

And they will have to move home in a poorer economic climate: worldwide. If governments and city authorities do not take the right steps, sea level rise could erode 4% of the global annual economy, says a separate study. That is, coast-dwellers could witness not just their towns and even cities washed away: they could see their prosperity go under as well.

Californian scientists report in the Public Library of Science journal PLOS One that they used machine learning techniques – in effect, artificial intelligence systems – to calculate what is most likely to happen as US citizens desert Delaware Bay, slip away from the cities of North and South Carolina, and flee Florida in the face of rising sea levels, coastal flooding and increasingly catastrophic windstorms.

“Sea level rise will affect every county in the United States … everybody should care about sea level rise, whether they live on the coast or not”

In the year 2000, a third of all the planet’s urban land was in a zone vulnerable to flood. By 2040, this could rise to 40%. In 2010, in the US, more than 120m citizens – that is nearly 40% of the entire population – lived in coastal counties. By 2020, this proportion could already be higher.

And by 2100, at least 13.1m people could be living on land likely to be inundated if sea levels rise by 1.8 metres. Except that they won’t: they will have already seen the future and moved away from it, to some settlement well away from the rising tides.

Those who might otherwise have purchased their abandoned seaside houses will be looking for somewhere safer and adding to the pressure on the housing market.

“Sea level rise will affect every county in the United States,” said Bistra Dilkina of the University of Southern California at Irvine, a computer scientist who worked with engineers to model the human response to the future.

She and her colleagues started from patterns of movement that began with Hurricane Katrina, in 2004, and Hurricane Rita a year later, both in Louisiana. They then let the algorithms take over the challenge of guessing what American families and businesses are most likely to do as the tides begin to flood the high streets.

Action promised

“We hope this research will empower urban planners and local decision-makers to prepare to accept populations displaced by sea level rise. Our findings indicate that everybody should care about sea level rise, whether they live on the coast or not,” she said.

The California team’s worst-case forecasts are based on a premise that the world takes no real action to combat sea level rise, which is driven by global warming powered in turn by fossil fuel emissions into the atmosphere on an ever-increasing scale.

But in Paris in 2015, more than 190 nations did agree to act: to contain global warming to “well below” 2°C by the century’s end. So far, very few have committed to sufficient action, and the President of the US has pronounced climate change a “hoax” and announced a withdrawal from the Paris Agreement.

Researchers in Austria report in the journal Environmental Research Communications that they decided to consider the potential economic cost worldwide of sea level rise alone. Scientists have been trying for years to guess the cost of flood damage to come: the latest study is of the impact of sea level rise and coastal flooding upon national economies worldwide.

The scientists considered two scenarios, including one in which the world kept the promises made in Paris, and one in which it did not, and made no attempt to adapt to or mitigate climate change.

Significant impact

By 2050 losses in each scenario would be significant and much the same. But by 2100, the do-nothing option promised to hit the gross domestic product – an economist’s favourite measure of economic well-being – by 4%.

Europe and Japan would be significantly hit; China , India and Canada hardest of all. If the world’s richest nations actually worked to limit climate change and adapt to the challenges ahead, the impact on the economy could be limited to 1%.

“The findings of this paper demonstrate that we need to think long term while acting swiftly,” said Thomas Schinko of the International Institute for Applied Systems Analysis in Austria, who led the study.

“Macroeconomic impacts up to and beyond 2050 as a result of coastal flooding due to sea level rise – not taking into account any other climate-related impacts such as drought – are severe and increasing.

“We, as a global society, need to further co-ordinate mitigation, adaptation and climate-resilient development and consider where we build cities and situate important infrastructure.”

This article was originally posted on the Climate News Network.
Cover photo of Houston, Texas by Vlad Busuioc on Unsplash
New report promotes CCA and DRR cooperation through the use of foresight methods

New report promotes CCA and DRR cooperation through the use of foresight methods

By Georgina Wade

The European research project PLACARD (PLAtform for Climate Adaptation and Risk reDuction) has released a follow up report to their 2018 foresight report, expanding on the importance of collaboration between Disaster Risk Reduction (DRR) and Climate Change Adaptation (CCA) communities.

            Through the establishment of a coordination and knowledge exchange platform, PLACARD aims to support multi-stakeholder dialogue and consultation between CCA and DRR research, policy and practice communities, and across scales. Specifically, the latest PLACARD report aims to promote cooperation through the use of foresight methods for policy and decision-makers.

Foresight methods help decision-makers explore and anticipate future developments through a range of forward-looking approaches that promote participants to think about, debate and shape the future in a participatory, inclusive, and action-oriented manner. In particular, these methods are useful for CCA and DRR collaboration due to their systematic, participatory, future-intelligence-gathering and medium-to-long-term vision-building process aimed at enabling present-day decisions and mobilising joint actions.

Figure 1: Schematic representation showing how CCA and DRR overlap.

With this report, PLACARD investigates the different methodologies, determining how they may be affectively applied to better integrate CCA and DRR in research, policy and practice.  An analysis of 20 of the most commonly applied foresight methods are reviewed with regards to their definition, strengths and weaknesses, form of application, and current application in CCA and DRR science and/or policy activities. In addition, the report aims to promote the application of foresight methods to CCA and DRR science and practice, and to contribute to the setting of a joint research agenda on foresight.

The research project has confirmed that the use of foresight methods can go beyond the current support to CCA and DRR research, policy and practice, and promote better connections and integration across the two communities.

 In fact, effective foresight may:

  • Enhance the effectiveness of participatory processes, cooperation and dialogue;
  • Produce salient knowledge and capacity building that is relevant for future decision-making and policy support;
  • Facilitate the understanding of issues and concepts such as complexity, uncertainty, non-
  • linearity, wildcards and surprises;
  • Generate levers that build flexibility into policy measures and across policy areas;
  • Address different time scales simultaneously (e.g., connect long-term CCA/prevention with short-term DRR/preparedness);
  • Be used in the context of trust building and the development of shared values;
  • Allow for the use of a holistic perspective in connecting different policy areas.

            PLACARD’s report concludes with a confirmed hypothesis – foresight methods and their practical application can be a useful tool to support decision-making in CCA and DRR, but that its implementation in Europe can be extended and further improved.

Download the full report here

Coverphoto by John Dal on Climate Visuals, Creative Commons.
Ancient Antarctic ice melt caused extreme sea level rise 129,000 years ago – and it could happen again

Ancient Antarctic ice melt caused extreme sea level rise 129,000 years ago – and it could happen again

By Chris Fogwill, Chris Turney and Zoe Thomas

Rising global temperatures and warming ocean waters are causing one of the world’s coldest places to melt. While we know that human activity is causing climate change and driving rapid changes in Antarctica, the potential impacts that a warmer world would have on this region remain uncertain. Our new research might be able to provide some insight into what effect a warmer world would have in Antarctica, by looking at what happened more than 129,000 years ago.

We found that the mass melting of the West Antarctic Ice Sheet was a major cause of high sea levels during a period known as the Last Interglacial (129,000-116,000 years ago). The extreme ice loss caused more than three metres of average global sea level rise – and worryingly, it took less than 2˚C of ocean warming for it to occur.

To conduct our research, we travelled to an area on the West Antarctic Ice Sheet and drilled into so-called blue ice areas to reconstruct the glacial history of this ice sheet.

Blue ice areas are areas of ancient ice which have been brought to the surface by fierce, high-density winds, called katabatic winds. When these winds blow over mountains, they remove the top layer of snow and erode the exposed ice. As the ice is removed by the wind, ancient ice is brought to the surface, which offers insight into the ice sheet’s history.

While most Antarctic researchers drill deep into the ice to extract their samples, we were able to use a technique called horizontal ice core analysis. As you travel closer to the mountains of the ice sheet, the ice that been brought to the surface by these winds progressively gets older. We then were able to take surface samples on a straight, horizontal line across the blue ice area to reconstruct what happened to the ice sheet in the past.

Drilling into blue ice. Professor Chris Turney, Author provided

Our team took many measurements. We first looked at the fine layers of volcanic ash in the ice to pinpoint when the mass melting took place. Alarmingly, the results showed that most ice loss happened at the start of Last Interglacial warming, some 129,000 years ago – showing how sensitive the Antarctic is to higher temperatures. We think it’s likely this melting started well before the ocean warmed by 2˚C. This is concerning to us today, as ocean temperatures continue to increase, and the West Antarctic is already melting.

We also measured temperature-sensitive water molecules across the blue ice area. These isotopes revealed a large shift in temperatures, highlighting a major gap in our record at the start of the Last Interglacial. This indicates a period of sustained ice loss over thousands of years.

This period of missing ice coincides with extreme sea level rise, suggesting rapid ice melt from the West Antarctic Ice Sheet. DNA testing of ancient microbes preserved in the ice revealed an abundance of methane-consuming bacteria. Their presence suggests that the release of methane gases from sediments under the ice sheet may have also played a role in accelerating the warming process.

The West Antarctic ice sheet can tell us a lot about the effect of warming ocean temperatures because it rests on the seabed. It’s surrounded by large areas of floating ice, called ice shelves, that protect the central part of the sheet. As warmer ocean water travels into cavities beneath the ice shelves, ice melts from below, thinning the shelves and making the central sheet highly vulnerable to warming ocean temperatures. This process is currently being researched on the West Antarctic Thwaites Glacier, nicknamed the “Doomsday Glacier”.

Using data from our fieldwork, we ran model simulations to investigate how warming might affect the floating ice shelves. These ice shelves protect the ice sheets and help slow the flow of ice off the continent. Our results suggest a 3.8 metre sea level rise during the first thousand years of a 2˚C warmer ocean. Most of the modelled sea level rise occurred after the loss of the ice shelves, which collapsed within the first two hundred years of higher temperatures.

These findings are worrying – especially if persistent high sea surface temperatures could prompt the larger East Antarctic Ice Sheet to melt, driving global sea levels even higher. But our findings suggest the West Antarctic Ice Sheet may be close to a tipping point. Only a small temperature increase could trigger abrupt ice sheet melt and a multi-metre rise in global sea levels.

At the moment, research suggests that global sea levels could rise between 45-82cm over the next century. However, it’s thought that Antarctica will only contribute around 5cm of this – most of this sea level rise will be caused by warmer ocean waters and the melting of the Greenland Ice Sheet. But based on our findings, Antarctica’s contribution could be much greater than anticipated.

Despite 197 countries committing under the Paris agreement to restricting global warming to 2˚C by the end of this century, our findings show that even minor increases in temperature could have far-reaching impacts.

This article was originally published on the Conversation.
Cover photo from pixabay.
Even looking at flood maps can’t convince coastal residents their homes will be underwater

Even looking at flood maps can’t convince coastal residents their homes will be underwater

By Risa Palm and Toby W. Bolsen

Advertisers understand that providing consumers with the facts will not sell products. To get people to stop and pay attention, successful advertising delivers information simply and with an emotional hook so that consumers notice and, hopefully, make a purchase.

Climate communication scientists use these same principles of messaging—visual, local, and dramatic—to provide facts that will get the public’s attention. Such messaging is intended to help people understand risk as it relates to them, and perhaps change their behavior as a result.

As social scientists studying the effectiveness of climate change communication strategies, we became curious about a particular message we found online. Some houses advertised for sale in South Florida were accompanied by banner ads with messages such as “Flooding hurts home value. Know more before you buy. Find out for free now.” The ads were sponsored by the First Street Foundation through its website The nonprofit foundation provides detailed aerial photos of present and future flooding as a consequence of rising sea level.

My colleague and I decided to survey residents of coastal South Florida to better understand how information affected their attitudes and opinions. Did these messages developed by a nonprofit organization change the perceptions of coastal residents who live in low-lying areas about the threat of coastal flooding as a result of sea-level rise?

Defining the danger to property by zip code

Many studies of climate change communication and response have been based on national surveys or more local reviews of counties and states susceptible to a range of coastal flooding. We focused our survey on a single region and a population at greatest risk: those who live in zip codes along the South Florida coast where the probability of flooding in local neighborhoods is extremely high.

Maps can be a way to see potential flood risk. [Image: floodiq/courtesy of the author]

With permission of the First Street Foundation to reproduce their maps that represent what flooding in the future might look like, we developed a survey to understand the effectiveness of tailored messages. How would this messaging impact residents’ beliefs about climate change and sea-level rise? We also asked if residents believed their communities and homes were at risk.

We surveyed more than 1,000 residents living in 166 zip codes in South Florida between October and December of 2018. All those surveyed were at risk from either the direct or indirect effects of flooding to their homes, including a decrease in property values, as coastal property is perceived as a less desirable destination.

We sampled residents of seven metropolitan areas, including Tampa-Saint Petersburg-Clearwater, Fort Myers, Key West, Miami-Dade County, Fort Lauderdale, West Palm Beach and Palm Beach, and Vero Beach. Half the sample received a map of their own city, rendered at a scale so that their city block was visible. The maps illustrated what could happen just 15 years from now at the present rate of sea-level rise if there were a Category 3 hurricane accompanied by storm-surge flooding.

[Photo: Asael Peña/Unsplash]

Does visual information make a difference?

The study was intended to assess how residents might perceive the vulnerability of their property and their communities to severe storms. We asked residents about their political affiliation and their support for policies such as zoning laws, gasoline taxes, and other measures to address climate change.

Surprisingly, we found that those who had viewed the maps were, on average, less likely to say they believed that climate change was taking place than those who had not seen the maps.

Further, those who saw the maps were less likely than those survey respondents who had not seen the maps to believe that climate change was responsible for the increased intensity of storms. Respondents who classified themselves as Republicans had the strongest negative responses to the maps.

Those who saw the maps were no more likely to believe that climate change exists, that climate change increases the severity of storms, or that sea level is rising and related to climate change. Even more dramatically, exposure to the scientific map did not influence beliefs that their own homes were susceptible to flooding or that sea-level rise would reduce local property values.

Consistent with national surveys, party identification was the strongest predictor of general perceptions of climate change and sea-level rise. However, the majority of homeowners denied that there was a risk to their property values, regardless of political affiliation.

What does it take to change minds?

We believe that the motivation of our respondents, their underlying beliefs when forming an opinion, is important when reflecting on these survey results. Specifically, people often process information or learn in a way that protects their existing beliefs or their partisan leanings.

In the case of our respondents’ general beliefs about climate change and its connection to sea-level rise, those who belonged to the Republican Party may have dismissed the maps either because they challenged their party’s stance on the issue or because they did not view the information as credible given their prior views. In the case of our respondents’ views about the future effects of sea-level rise on property values, all of the homeowners we surveyed, regardless of their partisanship, may have been motivated by their personal financial interests to reject the notion that sea-level rise would reduce their own property values.

It is important to emphasize that targeted information about climate change may lead to unintended effects. While accurate and easily absorbed information is important, it will take a much more nuanced approach to change the way people understand information. As advertisers well know, it takes more than facts to sell any product.

This article was originally published on The Conversation.
Cover photo by Epicurrence on Unsplash
Taking action on air pollution at city level to build urban resilience

Taking action on air pollution at city level to build urban resilience

By Emma Marsden and Bulganmurun Tsevegjav 

The Asian Development Bank (ADB) on 8–9 October hosted a regional inception workshop to kick start the implementation of the regional technical assistance titled “Strengthening Knowledge and Actions to Improve Air Quality” (TA 9608) at the ADB headquarters in Manila. The TA addresses urban air pollution, which has become a serious environmental and social problem in many of Asia’s cities, posing a major health risk, among other negative impacts, to their residents, particularly vulnerable groups.

About 98 percent of cities in Asia experience levels of fine particulate matter (PM2.5) beyond the internationally recognized World Health Organization (WHO) air quality guideline.1 Given this high level of exposure, several questions arise: What are the main causes and consequences of urban air pollution in Asian cities? Are national and city governments taking adequate measures to address the problem? How can city governments, including the energy and transport sectors, best tackle urban air pollution at the city level? How can lessons learned and best practices adopted in other countries and cities, such as the People’s Republic of China (PRC), be shared?

These questions sit behind the TA outputs and were at the heart of the dialogues during the regional inception workshop.

Major Sources of Air Pollution Presented in the Workshop. Source: Clean Air Asia. 2014. Mainstreaming Air Quality in Urban Development through South–South Twinning.

Highlights of the workshop

Around 80 participants (40% female) from government, non-governmental organizations, and civil society attended the workshop. Participants included national and city government officials from the five developing member countries (specifically, seven cities) targeted by the TA: Bangladesh (Faridpur), Mongolia (Erdenet), Pakistan (Peshawar and Sialkot), the Philippines (La Trinidad), and Viet Nam (Ho Chi Minh and Vinh Yen). Representatives from WHO and the International Labor Organization, academia, ADB Youth, and international health, energy, transport, and finance experts were also in attendance.

The two-day event was designed so that city-level participants without any technical knowledge of air quality management could benefit from the workshop sessions as much as the experts. The first sessions introduced the basic concepts of urban air pollution, major sources, and how it affects public health.

Conversations around air pollution are often focused on the perception that it is the outside air that is the most polluted. However, participants heard that in some countries indoor air pollution levels can be even higher that outside, and therefore cities also need to address it alongside outdoor air pollution. Policy and legislative, institutional, technological, and financial solutions, including low carbon technologies and the use of market-based instruments for air pollution control, were presented.

Following this, city representatives were given the opportunity to present the urban air pollution challenges they face in their cities and how the TA through its support for developing a Clean Air Action Plan can aid their current efforts.

Overall, the objectives of the remaining sessions were to: 

  • Provide information on the TA including project background, the overall approach, method, scope and deliverables.
  • Introduce the process of Clean Air Action Plan development, including case study examples from Mongolia, the Philippines, and Viet Nam.
  • Provide an opportunity for the country and city representatives to discuss their air quality issues and to prepare a draft of the workplan for development of the City-Level Clean Air Action Plans.

Following the regional inception workshop, city-level inception workshops are being held, from which the City-Level Clean Air Action Plans will be developed. To inform the action plans, the TA will refer to existing baseline data, and the TA team will also collect new data on the air quality situation and undertake analytical studies at the city level to fill in knowledge gaps.

Furthermore, policy and legislative, institutional, technological, and financial solutions will be evaluated, taking on board lessons learned and best practices from other countries and cities, including a technology transfer event planned for the PRC in late 2020.


Image: Indoor Air Quality Can Have a Large Impact on Health Outcomes in Cities. Source: B Tsevegjav, Presentation on Indoor Air Quality: Case from Mongolia. TA 9608 Regional Inception Workshop.

Background of the project

The TA project aims to increase the commitment of the selected countries to improve air quality management, helping the target cities to build a business case for investment through the preparation of City-Level Clean Air Action Plans, and investment plans that will see to its implementation.

The TA has three main outputs (also detailed in the diagram below):

  •  Output 1 focuses on “assessment” of air quality status and capacity for air quality management at city level, including monitoring of air quality levels in secondary cities using low cost monitors, which will help to raise political and public awareness and provide the scientific basis for taking action.  
  • Output 2 is oriented towards “solutions” and is intended to help cities identify applicable and deliverable policy and legislative, technological, and financial solutions to tackle their air pollution sources as identified by Output 1.   
  • Output 3 intends to build on these two outputs to “mainstream air quality management” through the development of City-Level Clean Air Action Plans that are backed by investment roadmaps and have stakeholder buy in.
Image: Key outputs of the ‘Strengthening Knowledge and Actions for Air Quality Improvement’ project

This article was originally posted on the Asian Development Bank’s Livable Cities Blog.
Cover Photo by Holger Link on Unsplash
2019 picks from the Acclimatise article archive – Climate impacts and extreme events

2019 picks from the Acclimatise article archive – Climate impacts and extreme events

By Acclimatise News

Our sixth and final article of top picks from our 2019 article archive features six articles related to climate impacts and extreme events.

Scientists have been saying it for a while – weather events are likely to grow more extreme as the climate changes. In fact, there is evidence that the frequency of some types of extremes have changed – particularly warm temperatures and heavy rainfall events. Extreme weather events have severe impacts on society and ecosystems in our current climate, posing significant disruption to the lives of the poor through the disruption of food availability, displacement, and associated health risks. 

To strengthen resilience and better recover from extreme weather events, it is important that vulnerable areas take the proper steps in adopting adaptation measures and building climate resilience. For over fifteen years, Acclimatise has provided world-leading advisory services, helping corporates, investors and governments integrate climate change risk into their business processes and build resilience.  

This New Climate – Episode 2: Running dry – Dealing with water scarcity

By Acclimatise News

In the second episode of This New Climate, host Will Bugler explores why it is so difficult to manage water resources and presents Water2Invest – a new tool that helps decision makers make smarter choices about managing water supply and demand. Water2Invest, aims to help decision makers to take the right choices when investing in solutions to tackle water scarcity, potentially providing a powerful new tool to help tackle this crisis.

Listen to the podcast here.

Asia’s water supplies threatened by melting glaciers

By Acclimatise News

The ‘third pole’, encompassing the Himalaya-Hindu Kush mountain range and the Tibetan Plateau, is the planet’s largest reservoir of ice and snow after the Arctic and Antarctic. In recent decades, this vital area has faced increasing risk from climate change. For the past 50 years, glaciers in the Himalayas and the Tibetan Plateau have been shrinking with the Tian mountains having already lost one quarter of their mass.

Read the full article here.

Climate change to cause havoc with Mediterranean water resources says European Commission

By Acclimatise News

The Mediterranean will face mounting challenges to manage its water supplies as climate change drives droughts and floods according to a report by the European Commission. The report, which focusses on the effects of 2˚C of warming, indicates that there is likely to be a divide between central and northern Europe, which can expect more rainfall overall, and the Mediterranean which will suffer drought.

Read the full article here.

From droughts to floods: the cost of climate change for India continues to mount

By Devika Singh

India is one of the most climate vulnerable countries on Earth. A land of such diverse topography and microclimates, it is exposed to a wide spectrum of climate risks. The seemingly endless oscillation from extreme heat and drought to extreme rain and floods, has left the country counting the cost of climate change in lost lives, livelihoods and in dollars.

Read the full article here.

The flooding emergency in Northern England is a policy failure not a freak of nature

By Will Bugler

In 2012, Acclimatise led the work for part of the UK Government’s own Climate Change Risk Assessment and identified flooding as a top risk for each of the sectors analysed in the report. Five years later in 2017, the UK Climate Change Risk Assessment Evidence Report presented evidence that climate change may lead to increased risks from flooding. Despite these repeated warning, government action on flooding has been piecemeal.

Read the full article here.

More than half the world could see ‘record-setting heat’ every year by 2100

By Sophie Turner

Research published in 2019 in the journal Nature Climate Change suggests that more than half of the world could see new temperature records set in every single year by the end of the century if global gas emissions are not reduced. These findings reinforce the need to reduce greenhouse gas emissions and the importance of adapting to and preparing for unprecedented temperatures over the coming decades.

Read the full article here.

Dengue outbreaks affect UCCRTF cities

Dengue outbreaks affect UCCRTF cities

By Jahangir Alam, Hasib Raman, Napoleon Manegdeg, Nilo Manangan

Four Asian cities supported by the Urban Climate Change Resilience Trust Fund (UCCRTF) reported severe dengue outbreaks from January to September 2019.  Reports from the health departments and medical institutions in La Trinidad and Malay, Philippines and in Faridpur and Patuakhali, Bangladesh showed an increase in the number of dengue patients in the period compared to the same period last year. Increased prevalence of dengue fever is linked to climate change due to increased rainfall, which leads to more standing water that provides favorable conditions for mosquitos to breed.

In total, 451 dengue cases were reported in La Trinidad, 338 dengue cases in Malay, 2,795 dengue cases in Faridpur, and 587 dengue cases in Patuakhali. The disease caused 20 deaths in the Philippine province of Aklan (where the municipality of Malay is located), two in Faridpur, and the death  of an eight-year old boy in La Trinidad and a nineteen-year old girl in Patuakhali.

Flooding increasingly threatens the health of people living in UCCRTF cities. Along with the direct losses, damage, and inconvenience caused by perennial flooding, most flood-prone cities experience associated health risks such as diarrhoea, leptospirosis, and dengue, among others. 

The link between dengue and the presence of water in the environment is well documented. The dengue carrying mosquitoes breed profusely in any place where clean standing water is present such as in ponds, creeks, canals, water tanks, containers, and flower pots. Dengue cases rise sharply during the rainy season and after flood events as there is more stagnant water in cities.

The main underlying cause of dengue outbreak in the four UCCRTF cities this year is the spike in mosquito population, which can be traced from increased number of mosquito habitats especially in frequently flooded and waterlogged communities in La Trinidad, Malay, Faridpur, and Patuakhali. A dengue larval survey in La Trinidad revealed the widespread presence of dengue carrier mosquito larvae in water bodies throughout the municipality.

Continuous rain in Faridpur in August 2019 has inundated several parts of the city leading to waterlogging in low-lying areas, which in turn has caused outbreaks of water and vector-borne diseases including dengue. Since dengue is linked to precipitation, flooding, and poor drainage, there might be an increase in seasonal dengue outbreaks with changing precipitation patterns in many parts of the world, if not properly addressed.

Community-led projects and dengue prevention

With no effective cure or preventive vaccine for the dengue virus, efforts to contain the disease focus on reducing the number of mosquitos and protecting people from bites.  There is a need for dengue-prone communities to maintain cleanliness and remove stagnant water, especially during the rainy season and after flooding, to prevent mosquitoes from breeding. As such, addressing flooding and flood risks and ensuring the environment is clean are priority resilience initiatives in the four UCCRTF cities: 

  • In La Trinidad, UCCRTF is working with the community to improve the flood control system along Balili River by expanding the volume capacity of the flood culvert. This is to improve flood flow and reduce perennial flooding in the adjacent strawberry fields.
  • Malay being a coastal town has numerous swampland areas which are ideal breeding grounds for dengue mosquitoes. The pilot community is evaluating the flood dynamics from which the team will implement nature-based solutions and green infrastructure in strategic portions of the main river. This will help reduce water runoff, decrease erosion of riverbanks, and reduce incidents of flooding and flash floods in the area. 
  • In Faridpur, the sustainable river project along a small section of the Padma River will improve drainage and flood flow and reduce waterlogging in the pilot community.
  • Patuakhali is one of the most flood prone cities in Bangladesh due to its location and low-lying elevation. The pilot community in Patuakhali is implementing a community-based solid waste management program that will improve environmental waste pollution and at the same time reduce waterlogging and clogging of drainage in the community.
La Trinidad’s “4S” strategy

Local government in the cities have supported the work of the community-led projects. For instance, the Provincial Health Office in La Trinidad has strengthened measures to check breeding sites of mosquitoes. “The flood control project will contribute to dengue control as it will reduce the presence of stagnant waters on the ground and help eliminate breeding sites of dengue-causing mosquitoes,” said Vicente P. Perez, Jr., municipal planning and development officer of La Trinidad, Benguet. “Lessening flooding would prevent creation of breeding sites,” he stressed.

The La Trinidad Municipal Health Office encourages upland communities to practice a “4S” strategy for disease control:

  1.  Search and destroy mosquito breeding sites;     
  2.  Self-protective measures of using mosquito repellent and wearing long sleeves; 
  3. Say yes to fogging; and     
  4. Seek early consultation when signs of the disease appear.

Building resilience is not limited to providing solutions to a single issue but creates spaces for co-benefits and more holistic change. The four cities have identified various flood mitigation measures as their priority community-led projects. These projects will build resilience against flooding. The overlap between flood mitigation, waste management, and health is clear as flood mitigation will reduce the build-up of stagnant waters left behind after floodwaters recede.

This article was originally published on the Asian Development Bank’s Livable Cities Blog.
Cover photo by Syed Ali on Unsplash