Category: Climate Change Impacts

Arctic warming: are record temperatures and fires arriving earlier than scientists predicted?

Arctic warming: are record temperatures and fires arriving earlier than scientists predicted?

By Christopher J White

It was a grim record. On June 20 2020, the mercury reached 38°C in Verkhoyansk, Siberia – the hottest it’s ever been in the Arctic in recorded history. With the heatwaves came fire, and by the start of August around 600 individual fires were being detected every day. By early September, parts of the Siberian Arctic had been burning since the second week of June.

CO₂ emissions from these fires increased by more than a third compared to 2019, according to scientists at the Copernicus Atmosphere Monitoring Service. The wildfires produced an estimated 244 megatons of CO₂ between January and August, releasing thousands of years’ worth of stored carbon.

The summer of 2019 was already a record breaker for temperatures and fires across the Arctic. Seeing these events unfold again in 2020 – on an even larger scale – has the scientific community worried. What does it all mean for the Arctic, climate change and the rest of the world?

A satellite image shows smoke and clouds swirling over Russia.
A blanket of smoke stretches more than 4.5 million square kilometres across central and northern Asia. July 24 2019. EPA-EFE/NASA EARTH OBSERVATORY

Sooner than predicted?

Even with climate change, the severe summer heatwave of 2020 was expected to occur, on average, less than once every 130 years. Wildfire observations in the Arctic are fairly limited prior to the mid-1990s, but there is no evidence of similarly extreme fires in the years before routine monitoring started.

Higher temperatures globally are likely to be driving the increase in wildfire frequency and duration. But modelling wildfires is difficult. Climate models don’t predict wildfires, and they cannot indicate when future extreme events will occur year-on-year. Instead, climate modellers focus on whether they are able to predict the right conditions for events like wildfires, such as high temperatures and strong winds.

And these climate model projections show that the kind of extreme summer temperatures we’ve seen in the Arctic in 2020 weren’t likely to occur until the mid-21st century, exceeding predictions by decades.

So even though an increasing trend of high temperatures and conditions suitable for wildfires are predicted in climate models, it’s alarming that these fires are so severe, have occurred in the same region two years in a row, and were caused by conditions which weren’t expected until further in the future.

Fire burns the understory of a boreal woodland.
The Arctic is warming at a faster rate than the global average. Yelantsevv/Shutterstock

Climate feedback loops

So what is causing this rapid change? Over recent decades, temperatures in the most northerly reaches of Earth have been increasing at a faster rate than the rest of the world, with the polar region heating at more than twice the rate of the global average.

The fires caused by these hot, dry conditions are occurring in remote and sparsely populated forests, tundra and peat bogs, where there is ample fuel.

But these extreme events are also providing worrying evidence of climate “feedback loops”, which were predicted to happen as the climate warms. This is where increasing concentrations of greenhouse gases in the atmosphere contribute to further warming by promoting events – like wildfires – which release even more greenhouse gas, creating a self-perpetuating process that accelerates climate change.

Record CO₂ emissions released from burning Arctic forests during the summer of 2020 will make future conditions even warmer. But ash and other particulates from the wildfires will eventually settle on the ice and snow, making them darker and accelerating their melting by reducing how easily their surface reflects sunlight.

Climate change is not the direct cause of this summer’s fires, but it is helping to create the right conditions for them. The extreme temperatures and wildfires seen throughout the Arctic in 2020 would have been almost impossible without the influence of human-induced climate change – and they are feeding themselves.

Ice surface with black stain from soot.
Soot-stained ice absorbs more of the sun’s heat and melts more quickly. Trifonov Aleksey/Shutterstock

What about the rest of the world?

When we think of the Arctic, we don’t tend to picture wildfires and heatwaves – we think of snow and ice and long, brutal winters. Yet the region is changing before our eyes. It’s too early to say whether the last two summers represent a permanent step-change, or new “fire regime”, for the Arctic. Only observations over a much longer timescale could confirm this.

But these record-breaking events in the Arctic are being fuelled by human influences that are changing our world’s climate sooner than many expected. With climate models predicting a future where already hot and fire-prone areas are likely to become more so, 2020’s record temperatures paint a worrying trend towards more of the same.

The Arctic is at the frontline of climate change. What we are witnessing here first are some of the most rapid and intense effects of climate change. While the impact is devastating – record CO₂ emissions, damaged forests and soils, melting permafrost – these events may prove to be a portent of things to come for the rest of the world.

This article was originally published on The Conversation.
Cover photo by Roxanne Desgagnés on Wikimedia Commons.
Mass migration set to increase as world warms

Mass migration set to increase as world warms

By Paul Brown

Climate change is now driving mass migration, which will only worsen unless governments take global heating seriously.

There is strong evidence that deteriorating environments caused by climate change are driving millions of people to resort to mass migration in their search for a better life, both within countries and across borders.

As temperatures rise these migrations will only increase, particularly in Latin America and India, which is predicted to overtake China as the country with the largest population by 2025.

An analysis of environment and migration, published in Nature Climate Change, of 30 studies of individual countries across the world shows that there is no one single factor that drives migration.

But most research has found that environmental hazards have a major influence. Rising temperature levels, changes in rainfall and single sudden events like hurricanes are all triggers.

Policies for improvement

The analysis, by the International Institute for Applied Systems Analysis (IIASA) in Austria and research partners across Europe, was undertaken to try to inform policy makers about how to avert mass human migration.

It points out that two of the most high-profile mass migration episodes in recent times – the Syrian refugee crisis in 2015 and the “migrant caravan” from Central America to the United States in 2018 – have been partly attributed to severe droughts in the countries concerned.

While some studies conclude that environmental factors were not the main driver of migration, most thought it was one of the primary causes. The analysis says governments should expect significantly higher migration flows in the future.

Perhaps surprisingly, given the publicity surrounding the issue, migrations were not centred on poor people trying to enter rich nations in Europe or North America. Instead, most movements were from the countryside to urban areas in the same country, particularly in agriculturally dependent countries, or from one middle-income country to another.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels”

People with particularly low incomes normally stayed where they were,  despite environmental pressures, because they had no way of financing a move, while richer people had the means to adapt to new circumstances and so they also stayed put.

“Environmental factors can drive migration, but the size of the effects depends on the particular economic and socio-political conditions in the countries,” explains the lead author Roman Hoffmann, from Germany’s Potsdam Institute for Climate Impact Research (PIK).

“In both low and high income countries, environmental impacts on migration are weaker – presumably because either people are too poor to leave and therefore essentially become trapped or, in wealthy countries, they have enough financial means to absorb the consequences. It is mainly in middle-income regions and those with a dependency on agriculture that we see strong effects.”

IIASA predicts future higher levels of environmental migration for countries in Central America, the Caribbean, Brazil and Argentina. In Africa it is the Sahel region south of the Sahara that is already drying out, and East Africa that has the highest potential for people migrating because of climate change.

Eyes on India

Perhaps the most disturbing prediction is that India, with 1.3 billion people and soon to be the most populous country in the world, is likely to see large migrations. The heat and floods in the country are already killing hundreds of people a year, and many millions who are still dependent on subsistence agriculture are struggling with changing climate conditions.

“Our research suggests that populations in Latin America and the Caribbean, several countries in sub-Saharan Africa – especially in the Sahel region and East Africa – as well as western, southern and south-east Asia, are particularly at risk,” says co-author Anna Dimitrova from the Vienna Institute of Demography of the Austrian Academy of Sciences.

While the report is aimed at preparing governments for migrations that will inevitably happen in the future, with difficult consequences for both the migrants and the host country, the research suggests the best way of averting the coming crisis is to tackle climate change and reduce further rises in temperatures.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels as well as simultaneously to enhance adaptive capacity, such as through improving human capital,” says Jesus Crespo Cuaresma, a researcher with the IIASA World Population Program and professor of economics at the Vienna University of Economics and Business. − Climate News Network

This article was originally posted on the Climate News Network.
Cover photo from Pikist.
Rivers flood, seas rise – and land faces erosion

Rivers flood, seas rise – and land faces erosion

By Tim Radford

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

This article was originally posted on The Climate News Network.
Natural disasters must be unusual or deadly to prompt local climate policy change, study finds

Natural disasters must be unusual or deadly to prompt local climate policy change, study finds

By Ali Mustafavi

Natural disasters alone are not enough to motivate local communities to engage in climate change mitigation or adaptation, a new study from Oregon State University found.

Rather, policy change in response to extreme weather events appears to depend on a combination of factors, including fatalities, sustained media coverage, the unusualness of the event and the political makeup of the community.

Climate scientists predict that the frequency and severity of extreme weather events will only continue to increase in coming decades. OSU researchers wanted to understand how local communities are reacting.

“There’s obviously national and state-level climate change policy, but we’re really interested in what goes on at the local level to adapt to these changes,” said lead author Leanne Giordono, a post-doctoral researcher in OSU’s College of Public Health and Human Sciences. “Local communities are typically the first to respond to extreme events and disasters. How are they making themselves more resilient — for example, how are they adapting to more frequent flooding or intense heat?”

For the study, which was funded by the National Science Foundation, Giordono and co-authors Hilary Boudet of OSU’s College of Liberal Arts and Alexander Gard-Murray at Harvard University examined 15 extreme weather events that occurred around the U.S. between March 2012 and June 2017, and any subsequent local climate policy change.

These events included flooding, winter weather, extreme heat, tornadoes, wildfires and a landslide.

The study, published recently in the journal Policy Sciences, found there were two “recipes” for local policy change after an extreme weather event.

“For both recipes, experiencing a high-impact event — one with many deaths or a presidential disaster declaration — is a necessary condition for future-oriented policy adoption,” Giordono said.

In addition to a high death toll, the first recipe consisted of Democrat-leaning communities where there was focused media coverage of the weather event. These communities moved forward with adopting policies aimed at adapting in response to future climate change, such as building emergency preparedness and risk management capacity.

The second recipe consisted of Republican-leaning communities with past experiences of other uncommon weather events. In these locales, residents often didn’t engage directly in conversation about climate change but still worked on policies meant to prepare their communities for future disasters.

In both recipes, policy changes were fairly modest and reactive, such as building fire breaks, levees or community tornado shelters. Giordono referred to these as “instrumental” policy changes.

“As opposed to being driven by ideology or a shift in thought process, it’s more a means to an end,” she said. “‘We don’t want anyone else to die from tornadoes, so we build a shelter.’ It’s not typically a systemic response to global climate change.”

In their sample, the researchers didn’t find any evidence of mitigation-focused policy response, such as communities passing laws to limit carbon emissions or require a shift to solar power. And some communities did not make any policy changes at all in the wake of extreme weather.

The researchers suggest that in communities that are ideologically resistant to talking about climate change, it may be more effective to frame these policy conversations in other ways, such as people’s commitment to their community or the community’s long-term viability.

Without specifically examining communities that have not experienced extreme weather events, the researchers cannot speak to the status of their policy change, but Giordono said it is a question for future study.

“In some ways, it’s not surprising that you see communities that have these really devastating events responding to them,” Giordono said. “What about the vast majority of communities that don’t experience a high-impact event — is there a way to also spark interest in those communities?”

“We don’t want people to have to experience these types of disasters to make changes.”

This article was originally posted on Oregon State University Newsroom.
Cover photo by Brigitte Leoni on Climate Visuals.
Hotter oceans make the tropics expand polewards

Hotter oceans make the tropics expand polewards

By Tim Radford

The tropics are on the march and US and German scientists think they know why: hotter oceans have taken control.

The parched, arid fringes of the hot, moist conditions that nourish the equatorial forest band around the middle of the globe are moving, unevenly, further north and south in response to climate change.

And the role of the ocean is made even more dramatic in the southern hemisphere: because the ocean south of the equator is so much bigger than in the north, the southward shift of the parched zone is even more pronounced.

Across the globe, things don’t look good for places like California, which has already suffered some of its worst droughts and fires on record, and  Australia, where drought and fire if possible have been even worse.

In the past century or so, carbon dioxide levels in the atmosphere have risen from what was once a stable average of 285 parts per million to more than 400 ppm, and global average temperatures are now at least 1°C higher than they have been for most of human history.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations. This is a result of global warming”

And although the fastest and most dramatic changes in the world have been in the coldest zones – and particularly the Arctic – the tropics, too, have begun to feel the heat.

Researchers have observed tropical fish moving into cooler waters; they have warned that some tropical plant species may soon find temperatures too high for germination; they have mapped tropical cyclones hitting further north and south with time, and doing more damage; and they have seen evidence that tropical diseases could soon advance even into temperate Europe.

But although satellite observations have revealed that the tropical climate zone has expanded beyond the formal limits known as the Tropics of Capricorn and Cancer, and is doing so at somewhere between a quarter and half a degree of latitude each decade, no one has been able to work out why the shift is more pronounced in the southern half of the globe.

Now a new study in the Journal of Geophysical Research: Atmospheres offers an answer. The expansion of the tropics has been driven by ocean warming.

And if that expansion is more obvious in the southern hemisphere, it is because there is more sea to have more impact.

Clear link

Researchers analysed water temperature patterns in the great ocean gyres, those giant circular currents that take warm waters to the poles and return cold water to the equatorial regions.

They matched satellite readings from 1982 – the first year in the series of measurements – with data from 2018, and compared these to measurements of tropical zone expansion.

The connection was clear: excess heat that had been building up in the subtropical oceans ever since global warming began had driven both tropical edges and ocean gyres towards the poles.

That is, the shift in the tropics wasn’t just one of those slow pulses of expansion and retraction, of cyclic change, that happen in a complex world. And more precisely, the tropics were expanding more clearly in those places where the gyres moved poleward.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations,” said Hu Yang of the Alfred Wegener Institute in Bremerhaven, Germany, who led the research. “This is a result of global warming.” – Climate News Network

This article was originally posted on the Climate News Network.
Cover image by Brocken Inaglory, via Wikimedia Commons
Heatwaves are an invisible killer – and the UK is woefully unprepared

Heatwaves are an invisible killer – and the UK is woefully unprepared

By Chloe Brimicombe

The COVID-19 pandemic continues to cause suffering around the world, but another killer has silently struck in summer 2020. With relatively little by way of official warning or advice on how people can stay safe, recent heatwaves may have cost thousands of lives across the UK and western Europe. And these extreme weather events are arriving more often and in longer, deadlier bouts.

Most deaths during heatwaves occur out of sight and among those who are most vulnerable, such as the elderly and those with pre-existing health conditions. Because heatwaves aren’t something we can see or touch – and are often greeted with joy – it’s often difficult for people to understand the risk they pose.

In mid-August 2020, the UK saw the longest stretch of daytime temperatures above 30°C since 1976, as well as the hottest August day (36.4°C) since the deadly 2003 heatwave. Throughout 2020, there have also been 16 “tropical nights”. These occur when night time temperatures stay above 20°C, which used to be rare in the UK. There were 44 recorded between 1960 and 2000, but there have been 84 since 2000. The number of heatwaves each decade has also risen on average by one and a half per decade since 1960.

The three heatwaves the UK experienced in 2019 led to 892 deaths. The last time the record temperatures of August 2020 were reached in 2003, more than 2,000 people died in the UK.

An elderly man is wheeled into the emergency room of an Italian hospital.
The August 2003 heatwave is thought to have killed as many as 35,000 people across Europe. EPA PHOTO/ANSA/Daniel Dal Zennaro

Climate change is projected to raise average temperatures in the UK by 5°C by 2070, making the kind of temperatures seen in the mid-August heatwave of 2020 the norm for summers of the future. That could amount to a daunting public health crisis, and one which few people are talking about.

For every 1°C above a daily average temperature in the summer months, the UK currently sees a 2% rise in the death rate.

Beating the heat

Up to 5,000 people could die each year as a result of heat in the UK by 2050. Elsewhere, longer and hotter heatwaves are likely to wreak havoc on infrastructure built in a cooler past. Railway tracks will bucklebridges will sag and reservoirs could dry up. More than 300 households in West Sussex went without water for five days this summer.

Despite all this, heatwaves don’t even carry a Met Office weather warning, like rain, wind or snow. In the government’s national risk register, heatwaves are described as being more likely to occur than coastal and river flooding, and the scale of the damage they cause is similar. But from 2000 to 2019, there have been 68 journal articles published on heatwaves in the UK, versus 1,766 on floods. The amount of research attention and funding that heatwaves receive compared to flooding is tiny, even though extreme heat can trigger storms which themselves cause flash flooding.

Many researchers, including me, think the UK government’s handling of heatwaves is inadequate. As Bob Ward, policy director of the Grantham Research Institute on Climate Change at the London School of Economics said in 2018: “The lack of communication by government departments and agencies about the risks of heatwaves is contributing to the death toll every year.”

England has the heat health plan to coordinate relief efforts during heatwaves. It’s an emergency response run by Public Health England (which is in the process of being dismantled by the government) and informed by Met Office forecasting. When a heatwave is expected, warnings are sent to hospitals and care homes to take necessary precautions, like deploying fans and air conditioning.

The plan is only used from June 1 to September 15. If three consecutive days with hot temperatures pass outside those dates, there’s no emergency response mandated by the heat health plan. Nor would an event outside those dates even qualify for the official definition of a heatwave. But as February 2019 proved, heatwaves can arrive in the UK outside of official British summertime.

A spinning fan sits on a windowsill.
The UK’s heat health plan should go further to help adapt to extreme heat. Tim Roberts Photography/Shutterstock

The heat health plan only covers England, and since it’s an emergency response that’s only enacted in the health sector, the plan doesn’t allow for adaptations where they’re most needed to save lives. Overheating occurs in 20% of UK homes during a normal summer and it can lead to potentially fatal heat stroke. This is the cause of most preventable heatwave deaths and it demands an adaptation plan from the government that includes retrofitting homes and building new housing that doesn’t overheat.

Workplaces also need a legal maximum temperature at which people can stop working during bouts of extreme heat. In Latin America, working throughout heatwaves has been linked to kidney disease.

Heatwaves will continue to grow in intensity, duration and frequency without action on climate change. An emergency response once one has been declared is not enough. As extreme heat becomes routine, we must adapt our homes, roads and other infrastructure to save lives.

This article was originally posted on The Conversation.
Annual planetary temperature continues to rise

Annual planetary temperature continues to rise

By Tim Radford

More than 500 scientists from 61 countries have again measured the annual planetary temperature. The diagnosis is not good.

Despite global promises to act on climate change, the Earth continues to warm. The annual planetary temperature confirms that the last 10 years were on average 0.2°C warmer than the first 10 years of this century. And each decade since 1980 has been warmer than the decade that preceded it.

The year 2019 was also one of the three warmest years since formal temperature records began in the 19th century. The only warmer years – in some datasets but not all – were 2016 and 2015. And all the years since 2013 have been warmer than all other years in the last 170.

The link with fossil fuel combustion remains unequivocal: carbon dioxide levels in the atmosphere increased by 2.5 parts per million (ppm) in 2019 alone. These now stand at 409 ppm. The global average for most of human history has hovered around 285 ppm.

Two more greenhouse gases – nitrous oxide and methane, both of them more short-lived – also increased measurably.

“This millennium has been warmer than any comparable period since the Industrial Revolution”

The study, in the Bulletin of the American Meteorological Society, is a sobering chronicle of the impact of climate change in the decade 2010-2019 and the year 2019 itself. It is the 30th such report, it is signed by 528 experts from 61 countries, and it is a catalogue of unwelcome records achieved and uncomfortable extremes surpassed.

July 2019 was the hottest month on record. Record high temperatures were measured in more than a dozen nations across Africa, Europe, Asia and the Caribbean. In North America, Alaska scored its hottest year on record.

The Arctic as a whole was warmer than in any year except 2016. Australia achieved a new nationally average daily temperature high of 41.9°C on 18 December, breaking the previous 2013 record by 1.6°C. But even Belgium and the Netherlands saw temperatures higher than 40°C.

For the 32nd consecutive year, the world’s alpine glaciers continued to get smaller and retreat further uphill. For the first time on record in inland Alaska, when measured at 26 sites, the active layer of permafrost failed to freeze completely. In September, sea ice around the Arctic reached a minimum that tied for the second lowest in the 41 years of satellite records.

Catalogue of extremes

Global sea levels set a new high for the eighth consecutive year and are now 87.6mm higher than the 1993 average, when satellite records began. At a depth of 700 metres, ocean temperatures reached new records, and the sea surface temperatures on average were the highest since 2016.

Drought conditions led to catastrophic wildfires in Australia, in Indonesia, Siberia and in the southern Amazon forests of Bolivia, Brazil and Peru. And around the equator, meteorologists catalogued 96 named tropical storms: the average for 1981 to 2010 was 82. In the North Atlantic, just one storm, Hurricane Dorian, killed 70 people and caused $3.4bn (£2.6bn) in damage in the Bahamas.

“This millennium has been warmer than any comparable period since the Industrial Revolution. A number of extreme events, such as wildfires, heatwaves and droughts, have at least part of their root linked to the rise in global temperature,” said Robert Dunn, of the UK Met Office, one of the contributors.

“And of course the rise in global temperature is linked to another climate indicator, the ongoing rise in emissions in greenhouse gases, notably carbon dioxide, nitrous oxide and methane.” – Climate News Network

This article was originally posted on the Climate News Network.
Cover image by NaveenNkadalaveni, via Wikimedia Commons
Video: The global coffee crisis is coming

Video: The global coffee crisis is coming

Coffee is one of the most popular commodities on Earth. It’s grown by nearly 125 million farmers, from Latin America to Africa to Asia. But as man-made climate change warms the atmosphere, the notoriously particular coffee plant is struggling. Places like Colombia, which once had the perfect climate to grow Arabica coffee, are changing. Now, experts estimate the amount of land that can sustain coffee will fall 50 percent by 2050. It’s not just a crisis for consumers but for the millions who have made a livelihood out of growing coffee.

Cover photo by Hans Ripa on Unsplash.

250 million coastal dwellers will face rising floods

250 million coastal dwellers will face rising floods

By Tim Radford

Once again, researchers confirm that coastal dwellers can expect worse floods, more often and more expensively.

In the next 80 years flooding around the planet’s land masses is likely to rise by almost 50%, endangering many millions of coastal dwellers.

If humans go on burning ever greater volumes of fossil fuels, while destroying ever more natural forest, then another 77 million people could be at risk of flooding, a rise of 52%.

And these floods – increasingly frequent and extending over greater areas – will put at risk cities, homes, resorts and industries valued at more than $14 trillion (£10.7tn).

This sum alone is worth 20% of global gross domestic product, the economist’s preferred indicator of economic health and wealth, according to a new study in the journal Scientific Reports.

The researchers built their argument on historic data from 681 tide-gauge stations around the world to model the growing hazard at 10,000 coastal locations.

“Compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change”

They conclude that the land area exposed to extreme flood will increase by more than 250,000 sq kms – an increase of 48% – to 800,000 sq kms, a threat to 252 million people.

“A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting. Climate change is also increasing the frequency of extreme seas, which will further increase the risk of flooding,” said Ebru Kirezci of the University of Melbourne, Australia, who led the study.

“What the data and our model are saying is that compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change.”

None of this should come as a surprise to civic authorities, governments, hydraulic engineers and oceanographers: researchers have been warning for years that coastal floods driven by global heating will end up costing colossal and seemingly ever increasing sums.

On a global scale, and on regional examination, the story remains the same, and wealthy and developed societies in Europe and the US face the same rising tide of hazard as the world’s poorest in the crowded coastal cities of Africa and Asia.

Estimate too low?

A mix of more extreme storms and storm surges, combined with ever higher sea levels, will sweep away the world’s beaches and turn millions of comfortable US citizens into climate refugees.

It is even possible that researchers have under-estimated the hazard, simply because satellite-based measurements may have misread precise land elevation: in some cases, too, coasts are sinking independently of sea level rise.

The latest study identifies a series of flood “hotspots” around the world. These include south-eastern China, Australia’s Northern Territory, Bangladesh, West Bengal and Gujarat in India, the US states of North Carolina, Virginia and Maryland, and north-west Europe including the UK, northern France and northern Germany. The new map of risks takes no account of existing flood defences, but highlights the levels of threat to come.

“This is critical research from a policy point of view, because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis for taking action,” said Ian Young, an engineer at the University of Melbourne, and a co-author.

“This data should act as a wake-up call to inform policy at global and local government levels so that more flood defences can be built to safeguard coastal life and infrastructure.” – Climate News Network

This article was originally posted on the Climate News Network.
Photo of New Orleans, after Hurricane Katrina had passed over. Image: By Master Sgt Bill Huntington, USAF  (public domain), via Climate Visuals
Human climate change causes Arctic’s record heat

Human climate change causes Arctic’s record heat

By Tim Radford

The coldest place in the Arctic has experienced record heat. Climate change has made this 600 times more probable.

An international team of scientists has pinned the strange weather and record heat in the Siberian Arctic firmly on human-induced climate change.

On average, from January to June, temperatures in the region have been 5°C hotter because the world’s cities have continued to consume ever-increasing levels of fossil fuels.

The researchers report that, without human help, such freak conditions could happen only once every 80,000 years or so. But a steady increase in greenhouse gas levels in the atmosphere for the last century or more has increased the chances of record temperatures – one Arctic Circle settlement, Verkhoyansk, normally one of the coldest places on Earth, recorded 38°C on 20 June – by a factor of 600.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering,” said Andrew Ciavarella, of the UK Met Office, who led the study.

“This research is further evidence of the extreme temperatures we can expect to see more frequently around the world in a warming global climate. Importantly, an increasing frequency of these extreme heat events can be moderated by reducing greenhouse gas emissions.”

Confidence grows

That climate change has come to the Arctic is not news: what is significant about the research by British, French, Swiss, Dutch, German and Russian meteorologists is the readiness to put the blame fairly on climate change, even for a freak event.

It has always been a given in the science that the mix of air pressure and temperatures around the world delivers a random pattern of change marked by extremes, and for decades scientists backed away from blaming any single flood, windstorm or heat wave as evidence of climate change. That has, in the last few years, changed.

Research teams have successively warned that climate change driven by human action had contributed to California’s most recent disastrous drought; that both calamitous floods and catastrophic bushfires in Australia were made more probable and more intense by rising greenhouse gas emissions; and that the signature of climate change driven by fossil fuel combustion was now detectable in daily weather changes almost anywhere around the globe.

But the signature of climate change in the Siberian Arctic has been pronounced, and the latest attribution study is confirmation of a new confidence in the data.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering”

In June, forest fires in Siberia consumed 1.15 million hectares and released about 56 million tonnes of carbon dioxide: this is more than the annual emissions from Switzerland or Norway.

The rising temperatures in the region have been grounds for extra alarm: permafrost in the Arctic Circle is a store of carbon that is increasingly being released as the ground thaws, to make Arctic warming even worse.

But the hazards of permafrost thaw are also direct: soils become more vulnerable to slip and slump, and there is already measurable damage to the infrastructure once supported by sediments and topsoils that used to be frozen solid all year round.

The region recorded one of the world’s worst oil spills in May, when an oil tank collapsed. The unseasonal and improbable heat has been coupled to an explosion of silk moths, bringing further caterpillar damage to conifer forests.

Even now such temperatures remain unlikely: the human component of climate change has simply reduced the frequency of such sustained temperatures to perhaps once every 135 years.

Little time left

But without rapid and drastic cuts worldwide in greenhouse gas emissions, towns like Verkhoyansk – which also shares the record for the coldest temperature in the northern hemisphere – could become a lot warmer, a lot more often before the century’s end.

“These results show that we are starting to experience extreme events which have almost no chance of happening without a human footprint on the climate system,” said Sonia Seneviratne, of the Swiss Federal Institute of Technology, known as ETH Zurich.

“We have little time left to stabilise global warming at levels at which climate change would lie within the bounds of the Paris Agreement.

“For a stabilisation at 1.5°C of global warming, which would still imply risks of such extreme heat events, we need to reduce our CO2 emissions by at least half until 2030.”

This article was originally posted on The Climate News Network.