Category: Climate Change Impacts

Climate change is making autumn leaves change colour earlier – here’s why

Climate change is making autumn leaves change colour earlier – here’s why

By Philip James

As the days shorten and temperatures drop in the northern hemisphere, leaves begin to turn. We can enjoy glorious autumnal colours while the leaves are still on the trees and, later, kicking through a red, brown and gold carpet when out walking.

When temperatures rise again in spring, the growing season for trees resumes. Throughout the warmer months, trees take carbon dioxide from the atmosphere and store it in complex molecules, releasing oxygen as a byproduct. This, in a nutshell, is the process of photosynthesis. The more photosynthesis, the more carbon is locked away.

We know that carbon dioxide is a major driver of climate change, so the more that can be taken out of the atmosphere by plants, the better. With the warmer climate leading to a longer growing season, some researchers have suggested that more carbon dioxide would be absorbed by trees and other plants than in previous times. But a new study has turned this theory on its head and could have profound effects on how we adapt to climate change.

Reaching the limit

The researchers, led by Deborah Zani at the Swiss Federal Institute of Technology, studied the degree to which the timing of colour changes in autumn tree leaves was determined by the growth of the plant in the preceding spring and summer.

Temperature and day length were traditionally accepted as the main determinants of when leaves changed colour and fell, leading some scientists to assume that warming temperatures would delay this process until later in the season. Studying deciduous European tree species, including horse chestnut, silver birch and English oak, the authors of the new study recorded how much carbon each tree absorbed per season and how that ultimately affected when the leaves fell.

Using data from the Pan European Phenology Project, which has tracked some trees for as long as 65 years, the researchers found in their long-term observational study that as the rate of photosynthesis increased, leaves changed colour and fell earlier in the year. For every 10% increase in photosynthetic activity over the spring and summer growing season, trees shed their leaves, on average, eight days earlier.

Climate-controlled experiments on five-year-old European beech and Japanese meadowsweet trees suggest what could be behind this unexpected result. In these trials, the trees were exposed to full sun, half shade or full shade. The results show that there is a limit to the amount of photosynthesis that a tree can carry out over a growing season. Think of it like filling a bucket with water. It can be done slowly or quickly, but once the bucket is full, there is nowhere for any more water to go.

A misty forest with trees displaying autumn colours.
Deciduous trees, which shed leaves in autumn, have a fixed amount of carbon they can absorb per season. Alex Stemmer/Shutterstock

This research shows that deciduous trees can only absorb a set amount of carbon each year and once that limit is reached, no more can be absorbed. At that point, leaves begin to change colour. This limit is set by the availability of nutrients, particularly nitrogen, and the physical structure of the plant itself, particularly the inner vessels which move water and dissolved nutrients around. Nitrogen is a key nutrient which plants need in order to grow, and it’s often the amount of available nitrogen that limits total growth. This is why farmers and gardeners use nitrogen fertilisers, to overcome this limitation.

Together, these constraints mean that carbon uptake during the growing season is a self-regulating mechanism in trees and herbaceous plants. Only so much carbon can be taken up.

Earlier autumn colours

In a world with increasing levels of carbon in the atmosphere, these new findings imply that warmer weather and longer growing seasons will not allow temperate deciduous trees to take up more carbon dioxide. The study’s predictive model suggests that by 2100, when tree growing seasons are expected to be between 22 and 34 days longer, leaves will fall from trees between three and six days earlier than they do now.

A pile of yellow and orange maple leaves with a dark red leaf in the middle.
Get ready for this happening a little sooner in the future. Greg Shield/UnsplashCC BY-SA

This has significant implications for climate change modelling. If we accept that the amount of carbon taken up by deciduous trees in temperature countries like the UK will remain the same each year regardless of the growing season, carbon dioxide levels will rise more quickly than was previously expected. The only way to change this will be to increase the capacity of trees to absorb carbon.

Plants that aren’t limited by the amount of nitrogen available may be able to grow for longer in the warming climate. These are the trees which can take nitrogen from the air, such as alder. But these species will still lose their leaves at roughly the same time as always, thanks to less daylight and colder temperatures.

But on the upside, with the prospect of some trees losing their leaves earlier and others losing them at the time they do now, there might be the prospect of prolonged autumnal colours – and more time for us to kick through the leaves.


This article was originally published on The Conversation.
Cover photo by Timothy Eberly on Unsplash.
Polar link unites far extremes of north and south

Polar link unites far extremes of north and south

By Tim Radford

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” Climate News Network


Cover photo by W Bulach, via Wikimedia Commons
Social Movements Lead Recovery from Devastating Back-to-back Hurricanes in Central America

Social Movements Lead Recovery from Devastating Back-to-back Hurricanes in Central America

By Christina Schiavon

With a sequence and strength described by meteorologists as unprecedented, a pair of category 4 hurricanes, Eta and Iota, have slammed into Central America less than two weeks apart. Iota struck while accounting of the ongoing damages of Eta was still underway, leaving the full magnitude of total damages from both hurricanes yet to be determined. What is known at the time of writing is that the death toll, currently nearing 200, continues to grow, while more than 200,000 are without homes and millions more are impacted by the combined effects of the hurricanes and the ongoing COVID-19 pandemic.

Faced with voids in government support, particularly in two of the hardest-hit countries, Honduras and Guatemala, social movements have stepped in to carry out essential needs assessments and emergency relief efforts. Simultaneously, movements are coordinating at the regional level to ensure not only emergency relief, but a just recovery grounded in radical self-management and mutual support, building upon a people-to-people model popularized by Puerto Rican social movements in the wake of Hurricane Maria in 2017. Grassroots International has launched an emergency appeal to support these efforts in Central America and is in close contact with partners on the ground. The following is some initial analysis of the situation shared by movement partners on the frontlines of the crisis

CLIMATE CHAOS, COVID AND CORRUPTION – A DEADLY COMBINATION

In the midst of a record-breaking Atlantic hurricane season, that Eta struck Central America just as the US withdrawal from the Paris Climate Agreement became official could not be more tragically ironic. The Honduran government rightly pointed to the Eta catastrophe as yet another example of the uneven impacts of climate change, with countries that have contributed least to global emissions often among those hit the hardest. What it failed to acknowledge, however, was its own promotion of environmentally destructive projects and its complicity in the extreme suffering of its population at present, particularly among peasant, Indigenous and Afro-descendent communities that have faced systemic marginalization and repression since the country’s military coup of 2009.

Miriam Miranda of the Black Fraternal Organization of Honduras (OFRANEH), representing Afro-Indigenous Garífuna communities, connects multiple dots as she puts the current situation into context. She explains that Hurricane Mitch, which ravaged the country over two decades ago, followed by numerous other manifestations of climate chaos, provided ample warning of Honduras’ great vulnerability, yet:

There does not exist any disaster prevention strategy on the part of the government, nor has any sort of national disaster response been prepared… The very difficult situation we’re in not only lays bare the lack of prevention, but also how corrupt governments and political classes do not plan to save lives.

Miranda adds that the extent of devastation is also a direct result of government policies supporting expansion of palm oil plantations and other extractive industries, often involving violent displacements of the communities inhabiting the land. As a result:

Many parts of Honduras’ mountains have been destroyed, and many watersheds have been destroyed to such a degree that heavy rains are converted into a threat for the whole of the Honduran population.

Communities already inundated with water are receiving more water, Miranda laments, and the natural systems that could have helped to protect against flooding such as wooded areas have been largely destroyed. Furthermore, land clearings for plantations and megaprojects have not only left the land degraded and more prone to flooding, but have pushed communities onto marginal lands, making them particularly vulnerable to landslides and other dangers when storms strike. This is why, “In a city like San Pedro Sula, there are thousands of displaced peoples, thousands of people, including Garífunas, who lost absolutely everything due to living in high-risk zones.”

Faced with such conditions, OFRANEH is supporting emergency relief efforts, as it has throughout the COVID pandemic, while continuing to mobilize against their people’s displacement and increased vulnerability in the face of stronger and more frequent climate shocks. Such work forms a core part of OFRANEH’s approach to Black and Indigenous liberation.

Representatives of the Peasant Unity Committee (CUC) of Guatemala describe a similarly dire situation, with “dozens of flooded and isolated communities, damaged houses and infrastructure, hundreds of hectares of peasant crops completely lost to overflowing rivers, absence of shelters and overcrowding of families,” adding that: “As with other tragedies, the government response has been absent, slow or inefficient.” Situations of overcrowding among evacuees, both in Guatemala and Honduras, are particularly concerning given that both countries are still reeling from COVID-19, with government inaction contributing to skyrocketing rates of the virus in both countries. The UN Office for the Coordination of Humanitarian Affairs (OCHA) was already sounding the alarm on new outbreaks of the virus within makeshift shelters of Hurricane Eta victims before Iota struck.

CUC has lambasted the Guatemalan government for the inadequacy of its response in this moment of greatest need, in contrast to “the hundreds of thousands of quetzals (Guatemalan currency) that have been spent to mobilize police and military personnel who only carry fear and anxiety during states of exception,” including violent evictions of peasant and Indigenous communities from their lands. Government misuse and abuse of resources in the face of the combined COVID and climate crises have been similarly called out by OFRANEH and by other movements in the region. The regional coordinating body of peasant movements, CLOC-Vía Campesina (the Latin American Coordination of Rural Organizations), sums it up that:

In countries with neoliberal governments, we’ve seen much corruption in the face of the pandemic, and now the hurricanes, along with a lack of disaster prevention and support plan for the people. This has generated loss of human lives, together with infrastructural and economic losses. Under such circumstances, we reaffirm the refrain “Only the people save the people (Solo el pueblo salva al pueblo).”

“SOLO EL PUEBLO SALVA AL PUEBLO”

Taking this refrain to heart, social movements have been among the first responders in the aftermath of Eta and now Iota, conducting needs assessments and emergency relief in communities that have lost nearly everything yet are largely cut off from any other forms of support. In Guatemala, where impacts have been more confined to particular parts of the country, CUC has put out a call for support to impacted peasant communities, reminding Guatemalans that:

During these months of pandemic, the foods that have arrived at the tables of Guatemalan families have been provided by the hands of peasants who have not stopped working from sunrise to sunset to produce food, many of whom have now lost crops, animals, clothing and housing.

At the regional level, CLOC-Vía Campesina has formed an emergency committee that is coordinating directly with government, UN and nongovernmental bodies on emergency relief efforts, as well as coordinating with global allies like Grassroots International to bring direct support to movements on the frontlines of the crisis for the rebuilding of homes, farms and infrastructure. At the same time, they are pushing for a just recovery process over the medium and longer terms, supported by “progressive public policies that respect people’s lives and that support peasant agriculture.” A key component of this vision is a rebuilding of now-devasted food and agricultural systems with an orientation toward food sovereignty, in which communities are empowered to feed themselves and the broader population through diverse, resilient food systems. According to La Vía Campesina Honduras:

The agricultural sector has suffered its greatest destruction in the last 20 years; the losses are millions and incalculable. Until now the production of basic grains such as corn, rice, beans, vegetables that are basic products for food sovereignty have disappeared up to 80%, likewise thousands of hectares of coffee in the hands of small producers have been affected in the different regions of the country as a result of landslides and floods… Livestock has drowned.

Rebuilding from such devastation, as underscored by CLOC-Vía Campesina, will require “promoting the production of agroecological food, short circuits (of food transport) and healthy communities to avoid hunger” as well as “expanding the production of agri-food chains, transport, storage and distribution in nearby markets, native seeds, natural medicine and healthy consumption.” These are among the priorities that social movements are both calling for and making steps toward, even as they confront the extreme emergency needs of the present.

For Grassroots international’s Solidarity Program Officer for Latin America, Jovanna Garcia Soto, who has been coordinating directly with movement partners on the emergency appeal, the current crisis “brings back overwhelming memories of what happened when Hurricane Maria struck my archipelago, Puerto Rico, whose ultra-neoliberal government, like the governments of Honduras and Guatemala, placed the interests of capital above those of the people.” Another parallel she sees is how both the response by movements in Puerto Rico and by movements today in Central America demonstrate how community solutions based on mutual support and self-management save lives:

This is the path for a just recovery and the way to win the self-determination of our peoples. In these critical moments we have to stand up in solidarity with the Central American people impacted by hurricanes Eta and Iota. Our solidarity will define life or death, as we support grassroots groups and social movements organizing on the frontlines of the crisis now and working to dismantle the oppressive system over the long term. They are the backbone of the change towards a just and dignified world.


This article was originally posted on Relief Web.
Engulfed by the sea: the loss and damage from climate change

Engulfed by the sea: the loss and damage from climate change

By Gladys Habu

People from the Solomon Islands are experiencing profound loss and damage from climate change every day. Guest blogger Gladys Habu calls on the global community to recognise these losses, and act.

Aerial view of Honiara, Solomon Islands
Honiara, the capital city of Solomon Island, has seen 41 tropical cyclones passing within 400km, causing devastating damage (Photo: copyright Guus Schuijl)

I remember the first time I noticed the real, visible impacts of climate change. It was December 2009 and I was 14. My family and I were out in our little boat, visiting our beloved island called Kale.

With its white sandy beaches, clear waters and lush forests, Kale was a jewel between the ocean and the sky. It was a much-loved spot for people living on the Northwest of the Solomon Islands’ Isabel Province and a significant part of our cultural heritage.

My grandfather and his family lived here decades ago. They had a big family home and a garden where they cultivated root crops. Mangroves hugged the coastline, home to mud clams, crabs and more. People fished aplenty, turtles came ashore to lay their eggs, and the megapode birds nested in great numbers.

But as we approached Kale that day, I realised the island was threatened – slowly disappearing before my eyes.

An island
The island of Kale in 2009 (Photo: copyright Gladys Habu)

Fast forward to 2014 and Kale was completely submerged underwater. The beautiful life and culture that once thrived there, now engulfed by the sea.

Sea level rise and other climate change impacts took away an irreplaceable part of our livelihood. Sadly, my children will never know the island I loved so dearly.

Washed away

Kale has gone but our losses do not stop there. Climate change continues to ravage many of our coastal communities as the rising sea erodes our shores.

We do what we can to limit the damage – building stone walls along the coast to protect what’s left, planting new mangroves and constructing new houses on higher stilts with semi-permanent material over traditional (‘bush’) material. But these efforts to adapt have their limits.

Wall made of stones that divides land and sea
Locals built walls to protect the island from the increasing sea levels (Photo: copyright Gladys Habu)

Many of our houses have been damaged, displacing families from their normal ways of life. Displacement brings problems relating to land rights. In the Solomon Islands, land is owned either through the patrilineal or the matrilineal system and passed on from generation to generation.

Frequent moving of houses affects the traditional lineage norms and leads to social conflict within the community. With the limited land we have, it is becoming very difficult to find space for new homes. For many Solomon Islanders, relocating is not as simple as just getting up and leaving.

Climate change is also destroying our mangroves, the delicate ecosystems they support and the biodiversity that flourish there. One example is the mangrove mud clams – called Keu in my father’s dialect (Zabana) – a common source of protein our people rely on so heavily.

As rising seas overwhelm our shores and devastate our mangroves, our Keu is struggling. Areas that once yielded plentiful harvests are now barren.

Poisoned by salt

As the shoreline recedes, nearby freshwater systems are becoming mixed with salt water. People are forced to travel great distances to get clean water for drinking and cooking. These trips are usually made in a wooden canoe that leaves those venturing out at the mercy of our increasingly unpredictable weather.

Between 1969 and 2010, 41 tropical cyclones passed within 400km of the capital (Honiara). This is an average of one cyclone per season, but you can never say when a cyclone will hit. It’s not always safe to paddle far out from home.

These are just some examples of the damage and loss of climate change, and the devastating and far reaching impacts they have on our people.

I’ve just turned 25, and yesterday I went out to where Kale used to be. As we drew nearer by boat, I saw one remaining dead stump, still intact. The terns were all lined up on this last exposed bit of the island. We were able to drive our outboard motor right over the top of where our beautiful white sandy beaches once were.

Branches poke through the water, showing where an island used to be
The island of Kale in 2014, submerged under the sea (Photo: copyright Gladys Habu)

The life of Kale is now trapped under the turquoise ocean surface. Witnessing a whole island go into non-existence – it all feels so surreal. I am left questioning my own childhood memories of this wonderful island. Could we have done anything more to slow down or even prevent this loss?

My call to the world: recognise our losses

It saddens and angers me that we face these huge daily challenges, while millions around the world are fuelling the destruction we suffer, yet their own lives remain relatively unaffected.

The Solomon Islands, like many other Pacific Island countries, have made the tiniest of contributions to global warming, and the climate change and sea level rise that have resulted. Yet we wake up to face the negative impacts every single day.

And science tells us things are going to get worse: locked-in emissions set an unavoidable course of warming that will lead to sea-level rises at an unrelenting pace for years to come, as well as temperature rises and ocean acidification.

In the Solomon Islands we are fighters. We do what we can with the little we have to adapt and minimise further loss and damage. But we can’t do this alone.  

We need support from the global community. I appeal for voices from lesser represented countries directly affected by climate change to be amplified.

Let our experiences be told truthfully and loudly to those far and wide. The very real losses and damages from climate change must be recognised nationally and internationally, and policies put in place to make action, in every country, happen.


This article was originally published on IIED blogs.
Photo by Jenny Scott / Wikimedia Commons
Greenland is melting: we need to worry about what’s happening on the largest island in the world

Greenland is melting: we need to worry about what’s happening on the largest island in the world

By Jonathan Bamber

Greenland is the largest island in the world and on it rests the largest ice mass in the Northern Hemisphere. If all that ice melted, the sea would rise by more than 7 metres.

But that’s not going to happen is it? Well not any time soon, but understanding how much of the ice sheet might melt over the coming century is a critical and urgent question that scientists are trying to tackle using sophisticated numerical models of how the ice sheet interacts with the rest of the climate system. The problem is that the models aren’t that good at reproducing recent observations and are limited by our poor knowledge of the detailed topography of the subglacial terrain and fjords, which the ice flows over and in to.

One way around this problem is to see how the ice sheet responded to changes in climate in the past and compare that with model projections for the future for similar changes in temperature. That is exactly what colleagues and I did in a new study now published in the journal Nature Communications.

We looked at the three largest glaciers in Greenland and used historical aerial photographs combined with measurements scientists had taken directly over the years, to reconstruct how the volume of these glaciers had changed over the period 1880 to 2012. The approach is founded on the idea that the past can help inform the future, not just in science but in all aspects of life. But just like other “classes” of history, the climate and the Earth system in future won’t be a carbon copy of the past. Nonetheless, if we figure out exactly how sensitive the ice sheet has been to temperature changes over the past century, that can provide a useful guide to how it will respond over the next century.

A man walks over grassy land with glacier in background
Greenland’s glaciers contain around 8% of the world’s fresh water. Jonathan Bamber, Author provided

We found that the three largest glaciers were responsible for 8.1mm of sea level rise, about 15% of the whole ice sheet’s contribution. Over the period of our study the sea globally has risen by around 20cm, about the height of an A5 booklet, and of that, about a finger’s width is entirely thanks to ice melting from those three Greenland glaciers.

Melting As Usual

So what does that tell us about the future behaviour of the ice sheet? In 2013, a modelling study by Faezeh Nick and colleagues also looked at the same “big three” glaciers (Jakobshavn Isbrae in the west of the island and Helheim and Kangerlussuaq in the east) and projected how they would respond in different future climate scenarios. The most extreme of these scenarios is called RCP8.5 and assumes that economic growth will continue unabated through the 21st century, resulting in a global mean warming of about 3.7˚C above today’s temperatures (about 4.8˚C above pre-industrial or since 1850).

This scenario has sometimes been referred to as Business As Usual (BAU) and there is an active debate among climate researchers regarding how plausible RCP8.5 is. It’s interesting to note, however, that, according to a recent study from a group of US scientists it may be the most appropriate scenario up to at least 2050. Because of something called polar amplification the Arctic will likely heat up by more than double the global average, with the climate models indicating around 8.3˚C warming over Greenland in the most extreme scenario, RCP8.5.

Despite this dramatic and terrifying hike in temperature Faezeh’s modelling study projected that the “big three” would contribute between 9 and 15 mm to sea level rise by 2100, only slightly more than what we obtained from a 1.5˚C warming over the 20th century. How can that be? Our conclusion is that the models are at fault, even including the latest and most sophisticated available which are being used to assess how the whole ice sheet will respond to the next century of climate change. These models appear to have a relatively weak link between climate change and ice melt, when our results suggest it is much stronger. Projections based on these models are therefore likely to under-predict how much the ice sheet will be affected. Other lines of evidence support this conclusion.

What does all of that mean? If we do continue along that very scary RCP8.5 trajectory of increasing greenhouse gas emissions, the Greenland ice sheet is very likely to start melting at rates that we haven’t seen for at least 130,000 years, with dire consequences for sea level and the many millions of people who live in low lying coastal zones.


This article was originally published on The Conversation.
Cover photo by Filip Gielda on Unsplash
Climate change: New report shows global response is failing people in greatest need

Climate change: New report shows global response is failing people in greatest need

Global efforts to tackle climate change are currently failing to protect the people who are most at risk, according to new analysis by the International Federation of Red Cross and Red Crescent Societies (IFRC).

IFRC’s World Disasters Report 2020: Come Heat or High Water shows that the countries most affected by climate-related disasters receive only a fraction of the funding that is available for climate change adaptation and thus struggle to protect people from the aggravating effects of climate change.

IFRC’s Secretary General Jagan Chapagain said:

“Our first responsibility is to protect communities that are most exposed and vulnerable to climate risks.

“However, our research demonstrates that the world is collectively failing to do this. There is a clear disconnection between where the climate risk is greatest and where climate adaptation funding goes. This disconnection could very well cost lives.”

The failure to protect the people most vulnerable to climate change is especially alarming given the steady increase in the number of climate and weather-related disasters. According to the World Disasters Report, the average number of climate and weather-related disasters per decade has increased nearly 35 per cent since the 1990s.

Over the past decade, 83 per cent of all disasters were caused by extreme weather and climate-related events such as floods, storms, and heatwaves. Together, these disasters killed more than 410,000 people and affected a staggering 1.7 billion people.

The World Disasters Report also argues that the massive stimulus packages that are currently being developed around the world in response to the COVID-19 pandemic are an opportunity to address and reduce climate vulnerability. A recovery that protects people and the planet would not only help to reduce today’s risks but would also make communities safer and more resilient to future disasters.

Smart financing – with a focus on early warning and anticipatory action to reduce risks and prevent disasters before they happen – and risk reduction measures would both play a major role in protecting the most exposed communities.

Mr Chapagain said: Climate adaptation work can’t take a back seat while the world is preoccupied with the pandemic: the two crises have to be tackled together.

“These disasters are already on the doorstep in every country around the world. We must significantly scale up investment in climate smart actions that strengthens risk reduction and preparedness, alongside climate-smart laws and policies.

“With challenges like these, international solidarity is not only a moral responsibility, but also the smart thing to do. Investing in resilience in the most vulnerable places is more cost-effective than to accept continued increases in the cost of humanitarian response, and contributes to a safer, more prosperous and sustainable world for everyone.”

The World Disasters Report 2020: Come Heat or High Water can be downloaded here.


Cover image by Assam state, India, 2020/Indian Red Cross Society
Central Asia risks becoming a hyperarid desert in the near future

Central Asia risks becoming a hyperarid desert in the near future

By Natasha Barbolini

Around 34 million years ago, sudden climate change caused ecological breakdown in Central Asia. This ancient event, triggered by rapid drops in temperature and atmospheric carbon dioxide, permanently affected biological diversity in the region. Large areas of Mongolia, (geographic) Tibet and north-western China suddenly became hyperarid deserts with little vegetation cover – and stayed that way for almost 20 million years.

This was a surprising finding of new research I carried out with colleagues from across Europe and China, in which we reconstructed the past 43 million years of evolutionary history for the steppe, semi-desert and desert ecosystems of Central Asia (the biogeographical and political conceptions of “Central Asia” differ and we use the former: our research area is shown below).

Many scientists had previously thought that this region was forested for much of that time and only grew drier later on, culminating today in massive, exceptionally arid Asian deserts such as the Gobi and Taklimakan.

image showing a map, some plants and a cross section of some mountains and a desert
The modern Central Asian steppe-desert (A), characteristic plant families (B), and an altitudinal profile illustrating vegetation belts of the steppe subtypes (C). Science Advances 2020; 6: eabb8227

We found that fossil pollen combined with mammal fossils, geological and climatic evidence – all preserved inside ancient rocks – told a different tale. Ancient “wet” steppe-deserts that received enough precipitation to maintain high biodiversity already existed during the late Eocene (40 to 34 million years ago), but suddenly became much colder and drier over an event called the Eocene‒Oligocene Transition (EOT).

Scientists already knew that global climate cooling in this period caused the formation of a permanent Antarctic ice-sheet, but what happened on different continents is less clear. Our new study found that the lowlands of Central Asia became hyperarid deserts with little vegetation cover. The lack of food resources meant that larger animals were mainly replaced by small mammals like rodents, rabbits and hares.

Three bits of fossilised pollen viewed under a microscope
Scanning electron microscope (SEM) images of fossil pollen used to reconstruct the ancient ecosystems of Central Asia. Scale bars represent 5 micrometres (0.005 mm). Carina Hoorn and Fang Han, Author provided

This hyperaridity lasted for millions of years afterwards, and plants only recovered when the climate became temporarily wetter around 15 million years ago. But now, the major species were small, non-woody herbs, not the salt and drought- tolerant shrubs that had dominated before the ecological collapse. Despite large parts of Central Asia being very dry today, these shrubs (Nitraria and Ephedra) never again recovered their position of ecological prominence. We still don’t fully understand why, but it shows that populations can be permanently altered by sudden environmental changes even if widespread extinctions don’t occur.

This finding is particularly relevant today, because atmospheric carbon dioxide levels and climate are again changing rapidly. Given what we now know about the Asian steppe-desert’s climatic and ecological history, it is unlikely that these ecosystems will ever recover their present biological diversity if forced into a new state.

History repeats itself

The modern steppe-desert is the largest ecoregion of its kind in the world, hosting a lot more biodiversity than you might expect. Dry-adapted grasses and herbs support an array of wildlife, many of which are endemics (native to, and living only in, that region). These unique flora and fauna have evolved partly as a result of immense geological and climatic diversity: today Central Asia is home to some of the oldest deserts known, as well as the highest mountains outside of the Himalayas.

Flat grassy land with snowy mountains in the background
Meadow steppes in the Qilian Mountains of northern China, surrounded by alpine steppe and tundra. Topographic growth in the Tibetan region over many millions of years has created new high-elevation ecosystems for cold-tolerant biota to thrive. Xiaoming Wang / imaggeo.egu.eu, CC BY-ND

Ancient climate change and geological forces have shaped the steppe-desert through time. The collision of India with Asia, formation of the Tibetan Plateau and uplift of the Himalaya, Altai and Hangay mountain ranges created extreme altitudinal variation, as well as distinct rain shadows of dry land on the downwind side. This generated a mosaic of habitats, and in turn, an astonishing number of species who call the region home.

But now the steppe-desert’s biodiversity is under severe threat from human-induced climate change and land degradation. Growing seas of sand are claiming native steppes, imposing desertification at unprecedented rates. Evidence from the past shows us that this is a sign of impending ecosystem breakdown – and it will cause irreversible changes and loss of biodiversity if allowed to continue.

Claimed by the desert

Desertification in Asia has major implications for humans too. It now threatens almost half a billion people, many of whom are finding it increasingly difficult to make a living in communities dominated by agriculture. Crops are ravaged by drought, livestock are losing grazing pastures, and deserts are growing towards the cities.

Large sand dunes
Sand sea of the Taklimakan Desert. Similarly hyperarid deserts may have spread across Central Asia in the past as a result of rapid climate change. Matthias Alberti / imaggeo.egu.eu

Model predictions from the Intergovernmental Panel on Climate Change (IPCC) and recent climate records show that interior Asia is fast becoming one of the hottest and driest places on the planet. Major predicted changes include highly reduced vegetation cover and rapid, severe species losses, along with more unreliable rainfall and high dust emissions generated by widespread desertification and erosion.

This new hyperarid desert ecosystem phase would resemble the inhospitable, barren landscapes that spread 34 million years ago. Lessons from the past make it clear that current human-induced global changes must be urgently halted in order to preserve the Asian steppe, which has now become one of the world’s most endangered habitats.


This article was originally posted on The Conversation.
Cover photo by Wolfgang Hasselmann on Unsplash.

Drought and heat together menace American West

Drought and heat together menace American West

By Tim Radford

Climate change really is a burning issue. Simultaneous drought and heat are increasingly likely for more of the American West.

LONDON, 13 October, 2020 − The American West is about to get hotter. It is also about to get drier. To make things worse, extremes of heat and of drought will happen more often at the same time.

And to compound the damage, such simultaneous assaults are likely to extend over larger areas and become more intense and more frequent, thanks to climate change driven by profligate use of fossil fuels and other human decisions.

This is not a prediction based on computer simulations of the future. It is already happening, and the story can be traced − according to the journal Science Advances − in the narrative of hot spells and dry weather over the entire contiguous United States for the last 122 years.

Not only have combined hot and dry episodes increased in frequency, they have also grown in size in geographic terms. Where once they happened in confined localities, they now extend over whole regions, such as the entire West Coast, and parts too of the Northeast and the Southeast.

Another Dust Bowl?

“Dry-hot events can cause large fires. Add wind and a source of ignition, and this results in ‘megafires’ like the 2020 fires across the west coast of the United States. Drought and record-breaking heatwaves, coupled with a storm that brought strong winds and 12,000 lightning events in a span of 72 hours, caused more than 500 wildfires,” said Mohammad Reza Alizadeh, of McGill University in Canada, who led the research.

Heat extremes can be damaging or even devastating. So can drought. When the two coincide, their compound impact can be tragic. The study also suggested that in some way such double jeopardy events could be self-propagating: they could spread downwind, seriously bad news for the American West and other areas at risk.

Long before any fears of the climate emergency, the US Midwest was scarred by drought, and in the 1930s Oklahoma and Kansas in particular became a “Dust Bowl” and inspired the classic novel The Grapes of Wrath by the American writer John Steinbeck.

“We observed that concurrent dry and hot events of similar intensity are becoming more frequent,” said Mojtaba Sadegh, an engineer at Boise State University in Idaho, and the senior author.

“Our results point to an urgent need to take action to enhance resilience to compound hot and dry events”

“The difference is that, in the 1930s, lack of precipitation led to the local atmosphere becoming hotter, whereas in recent decades increased temperatures are driving aridity. The triggering mechanism for compound dry-hot events is changing from lack of precipitation to excess heat.”

The warning of worse to come coincides with news that California’s fires have become so bad that they warrant a new classification: the “gigafire”, with so much smoke emitted from the combined fires of California and Oregon that fumes have been detected in New York, in northern Europe, and far into the Pacific.

Researchers have repeatedly warned of the double hazard of heat and drought and the combined impact on the US, as a consequence of climate change driven by greenhouse gas emissions from power station chimneys and automobile exhausts, as well as destruction of the natural wilderness.

“This research raises an alarm about increasing frequency and intensity of compound hot and dry events,” said Dr Sadegh. “Three such events between 2011-2013 in the US caused $60bn (£46bn) in damages. Our results point to an urgent need to take action to enhance resilience to compound hot and dry events.” − Climate News Network


Cover photo by Madu Shesharam on Unsplash.
Climate migration: what the research shows is very different from the alarmist headlines

Climate migration: what the research shows is very different from the alarmist headlines

By David Durand-Delacre, Carol Farbotko, Christiane Fröhlich, Ingrid Boas

Predictions of mass climate migration make for attention-grabbing headlines. For more than two decades, commentators have predicted “waves” and “rising tides” of people forced to move by climate change. Recently, a think-tank report warned the climate crisis could displace 1.2 billion people by 2050. Some commentators now even argue that, as the New York Times noted in a recent headline “The Great Climate Migration Has Begun”, and that the climate refugees we’ve been warned about are, in fact, already here.

These alarming statements are often well-intentioned. Their aim is to raise awareness of the plight of people vulnerable to climate change and motivate humanitarian action on their behalf. But such headlines aren’t always accurate – and rarely achieve their intended effect.

Our main concern is that alarming headlines about mass climate migrations risk leading to more walls, not fewer. Indeed, many on the right and far right are now setting aside their climate denialism and linking climate action to ideas of territory and ethnic purity. In this context of growing climate nationalism, even the most well-intentioned narratives risk feeding fear-based stories of invasion when they present climate migration as unprecedented and massive, urgent and destabilising.

The risk is only made worse when headlines point to racialised populations from the global south as on their way to the European Union, the US or Australia: places already in the grips of moral panics about migration.

Nigel Farage stood in front of 'breaking point' anti-immigration poster.
A moral panic. Facundo Arrizabalaga/EPA

We do not deny that climate change influences migration. We cannot ignore the damage done to communities around the world by rising sea levels, worsening droughts and catastrophic forest fires. These raise new and serious challenges we must contend with. Yet the above narratives are misleading and damaging, when the concept of human mobility requires a deeper and more nuanced approach. It’s important we take these harsh realities seriously but avoid being too alarmist or seeing everything as being determined by the climate.

In general, we are concerned by the inaccurate portrayal of migration. People have always moved under the combined influences of changing environments, economies and sociopolitical dynamics. Climate migration is neither new nor extraordinary. It is not even that different from other forms of migration – climate migrants still tend to move to places they know or have connections to through their social networks.

These are key aspects of the idea of “climate mobilities”, which we developed in a Nature Climate Change commentary with 31 co-authors including anthropologists, geographers and political scientists. We point to how mobility in the context of climate change is highly diverse – what the vast body of empirical research on the subject has shown is far different from the image of mass movements of people moving abroad.

Instead, we see highly varied and fragmented climate-related journeys. For instance, climate mobility can take the form of short-term, short-distance movements, rural-to-urban migration, or voluntary immobility. Contrary to the alarmist rhetoric of mass international migration, most movements do not involve crossing a border. For instance a million Somalians were internally displaced by a drought in 2016-17 – this dwarfs the numbers involved in any international climate migration.

Two women and their babies walk across a dry desert.
The 2016 drought also displaced hundreds of thousands of people in Ethiopia – but again, almost all stayed within the country. UNICEF EthiopiaCC BY-NC-SA

Fully understanding climate mobilities requires a broader evidence base than is typically used. Many problematic narratives rely mainly on quantitative modelling, reading peoples’ experiences only through that lens. More research collaboration with the social sciences and humanities would improve our understanding, as these disciplines can provide a sensitivity to context that models alone will never achieve.

Affected people are telling their own stories

As we turn to a more diverse set of perspectives, affected people must themselves be included. They are already telling their own stories, in their own words. It’s crucial that we listen, especially when they contradict our research findings and personal intuitions. Listening to Pacific Islanders, for example, tells us that easy tales of “sinking islands” aren’t the whole story. Activists throughout the region have distilled their message of themselves as powerful actors in the fight for climate justice (and against climate migration) in the catchcry: “We are not drowning, we are fighting”.

Protesters hold up signs
‘We are not drowning, we are fighting’ Carol Farbotko, Author provided

Halfway across the world, interviews with young farmers in Senegal living in precarious situations found that, while climate change does threaten their livelihoods, it is not their key concern, and they do not see migration as a problem. They want stronger local government, more local economic opportunities and the choice to migrate regardless of cause, if it can mean a better life for them and their families.

Finally, research and reporting on climate migration needs to better consider destination areas. Policymakers throughout the global north are notoriously incapable and reluctant to take the complex realities of migration into account, to the point of sometimes disregarding the research they fund. Instead they justify anti-immigration policies such as the UK’s “hostile environment” by presenting the interests and desires of “native” populations as competing with those of new arrivals.

These narratives of inevitable economic and cultural conflict need to be challenged. For this, we can draw on a large body of work that shows migrants aren’t all rich and successful, or poor and excluded, and that successful projects take these differences into account, listen to migrants themselves and promote open dialogue with established populations.

Building an open, diverse, and accepting society in times of crisis and change is a difficult task. We should take care not to make it harder by promoting fear-based stories of climate migration.


This article was originally posted on The Conversation.
River deltas become even riskier as climate warms

River deltas become even riskier as climate warms

By Tim Radford

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network


This article was originally posted on The Climate News Network.
Cover image by Pinakpani on Wikimedia Commons.