Analysis

European summer heatwaves ten times more likely with climate change

  • 08 Dec 2014, 16:00
  • Robert McSweeney

CC 2.0: Andrew Bowden

Climate change is raising the odds of summer heatwaves in Europe by a factor of 10, according to new research from the Met Office. Over the past 10 to 15 years, the likelihood of a 'very hot' summer has risen - from once every 50 years to once every five years.

As the frequency of heatwaves increases, so do risks to human health. Improving resilience to high temperatures is critical to avoiding deaths caused by extended periods of hot weather, the authors say.

A record heatwave

The summer of 2003 was the hottest ever recorded for central and western Europe, with average temperatures in many countries as much as five degrees higher than usual.

Studies show at least 70,000 people died as a result of the extreme high temperatures. In August alone, France recorded over 15,000 more deaths than expected for that time of year, a 37 per cent rise in the death rate. The same month also saw almost 2,000 extra deaths across England and Wales.

To see how climate change is affecting the likelihood of heatwaves and other extreme events, researchers carry out attribution studies. These identify the fingerprints of human influence on observed changes in temperature, rainfall, and other climate parameters.

The heatwave was the first extreme weather event to be attributed to the human influence on the climate, with research suggesting it was made more than twice as likely because of climate change.

Now a new study, published in Nature Climate Change, finds that recent warming means a similar heatwave is even more likely. The increasing impact of humans on the climate means the risk of 'extremely hot' summers is now ten times greater than when the 2003 European heatwave struck.

Very hot summers every five years

In the new study, Met Office researchers ran their climate models twice: first with both natural climate fluctuations and manmade warming included, and secondly with only natural influences on the climate. They compared the results to see how rising temperatures have altered the odds of heatwaves in Europe.

You can see in the left-hand chart below how close the model simulations that include manmade warming (black line) are to actual recorded summer temperatures (red line). By contrast, modelled summer temperatures from a world where there's no human influence on the climate don't match up well with what scientists are seeing.

This shows summer temperatures can't be explained by natural variability alone, and climate change is playing a role, the paper explains.

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2014 on course to be the hottest year on record

  • 03 Dec 2014, 15:00
  • Robert McSweeney & Rosamund Pearce

UK Met Office

2014 is expected to be the among the hottest years since records began for the UK and the world, and may well prove to be the hottest, according to data from the World Meteorological Organisation (WMO) and the UK Met Office.

Rising temperatures are already contributing to greater risks of extreme weather, scientists warn.

A very warm and wet year for the UK

Met Office figures released today show the mean UK temperature for 2014 is 1.6 degrees Celsius above the long-term average. Currently 2006 is the warmest year since records began in 1910, but 2014 looks likely to replace it.

In England, where temperature records stretch back further, 2014 will be one of the warmest in the 350-year Central England Temperature (CET) record , the longest instrumental record in the world.

This year has also been a very wet one for the UK, and is on course to be the fourth wettest on record. A rainy December could even put 2014 over the annual record of 1337 mm set in 2000, says the Met Office.

A record-breaking year for the world

Globally, it seems likely that 2014 will be the hottest since records began in 1850. Average air temperature over the land and sea surface for 2014 so far is 0.57°C above the 1961-90 average. The previous high of 0.55°C warmer is held jointly by 2005 and 2010.

The ranking of hottest years is shown in the chart below. The red bars show years since the turn of the century, and show that for the most part the hottest years on record have occurred in the past decade or so.

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Meat and dairy consumption could mean a two-degree target is "off the table"

  • 02 Dec 2014, 23:59
  • Robert McSweeney

Wind turbine and cow | Shutterstock

Without a shift in meat and dairy consumption, limiting global temperature rise to two degrees is unlikely, says a new study by Chatham House.

The thinktank surveyed the meat and dairy eating habits of thousands of people in very different parts of the world. The findings show consumers underestimate the contribution of meat and dairy production to climate change, leading to them underestimate the effect that limiting meat and dairy consumption can have on limiting emissions.

The sizeable footprint of meat and dairy

The meat and dairy industry is responsible for 14.5 per cent of global greenhouse gas emissions. That's more than is produced by all cars, trains, planes and ships in the world.

Livestock emissions come directly from animals, from digestion and manure, and from transporting animals and producing their feed. Greenhouse gases are also released when forests are cleared to make way for pasture or for cropland in order to grow animal feed.

Chatham House _Livestock _Fig4

Livestock sector emissions by source. Chatham House.

China is the biggest consumer of both meat and dairy products, with the US, the EU and Brazil also in the top five. The top ten largest meat and dairy consuming countries are shown in the chart below.

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Education is "top priority" for climate change adaptation, study shows

  • 27 Nov 2014, 19:00
  • Robert McSweeney

Students in Swaziland | Shutterstock

Education does more to reduce deaths from climate-related disasters than economic growth, a new study finds. The researchers say education helps reduce vulnerability to disasters and enhances adaptation to climate change.

Financing adaptation

It's hard to pin down exactly how much money developing countries need to adapt to climate change. But some estimates suggest that it could be as much as $100 billion a year.

Countries have so far pledged $9 billion to the UN Green Climate Fund, which will provide money for adaptation and mitigation in developing countries.

Spending on climate change adaptation tends to be focused on large infrastructure projects, such as flood defences and irrigation systems. But new research, published in Science, suggests that investing in education could be a better way to reduce vulnerability to climate-related disasters.

Improving education reduces disaster deaths

The researchers argue that previous studies have concentrated too heavily on how economic development has reduced vulnerability to disasters such as floods, droughts and landslides.

They point to recent case studies that show improvements in education can give people the skills and knowledge to be better prepared for, and better able to recover from, natural hazards. For example, better-educated people in Cuba, Haiti and the Dominican Republic were faster at responding to hurricane alerts and recuperated more quickly once one had struck.

The researchers compare the influence economic growth and education have on the number of deaths from disasters for 167 countries across the world. They use Gross Domestic Product (GDP) per person as an indicator of economic growth and the number of women completing at least secondary school education as an indicator for education. They then cross-reference these with a database of climate-related disasters.

The results suggest that rising GDP has not reduced the number of deaths from climate-related disasters in the past four decades, while having a greater number of women in education has.

Better awareness of risk

So how does education reduce vulnerability to climate-related disasters? In an accompanying press release, co-author Dr Raya Muttarak explains:

"Education directly improves knowledge, the ability to understand and process information, and risk perception. It also indirectly enhances socioeconomic status and social capital. These are qualities and skills useful for surviving and coping with disasters."

Educated people have a better awareness of risk, the authors argue, and it gives them the knowledge and skills to adapt flexibly.

This is important because while scientists can make long-term projections of climate change, year-to-year weather variations mean they can't say exactly when a disaster will hit and how severe it will be. So a flexible approach to adaptation gives people and communities more capacity to cope when a disaster occurs.

Projecting future disaster deaths

When the researchers run simulations of future climate-related disasters, they find a similar pattern: improved education significantly reduces the number of deaths from disasters.

The results are shown in the graph below. The researchers use two pathways of how global education might change in the future: rapid expansion (red lines) and limited expansion (blue lines), which indicate, respectively, either substantial or minimal investment in education around the world.

The study models each education pathway against three scenarios of future change in climate-related disasters: no change (solid line), a 10 per cent increase (dashed line) and a 20 per cent increase (dotted line).

You can see that for each scenario of climate-related disasters, the improved education pathway results in fewer deaths.

The results suggest how "education is key in reducing disaster fatalities and enhancing adaptive capacity," says lead author Professor Wolfgang Lutz in the press release.

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Climate change set to increase extreme weather risk to UK population

  • 27 Nov 2014, 00:01
  • Robert McSweeney

Flooding in York | Shutterstock

The risk of heatwaves hitting the UK will increase ten-fold by 2100 if we don't cut greenhouse gas emissions, according to a new study of how climate change will affect extreme weather.  The UK will also be more at risk from flooding and drought says the new report, published by the Royal Society.

But the report also finds there are ways to prepare ourselves for what's to come, with a mix of large-scale engineering and natural measures to adapt to climate change making it possible to manage some climate risks.

Rising risks

The study uses climate models to estimate how the frequency of floods, droughts and heatwaves will change worldwide by the end of the century. It assumes population rises to around nine billion globally by 2100, and overlays projections of population growth to map where in the world the most people will be at risk from extreme weather.

Perhaps unsurprisingly, places with high populations tend to have more people at risk from climate extremes. For the UK, the combined effects of climate and population changes will increase the risk of exposure to heatwaves by a factor of more than 10 by the end of the century, the report says.

If we don't cut emissions, the risk of exposure to floods in the UK will increase four and a half times by the end of the century, and the risk of drought three times.

The risks posed by heatwaves grow particularly rapidly because older people who are more at risk from extreme heat will make up a larger chunk of global population by the end of the century, the report says.

The study produced maps which show how exposure to extreme weather will change. The areas of dark red show the greatest increase in people exposed to risk - in India, southeast Asia, parts of central Africa and western Europe.

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Scientists dig deep into earth's history for clues to El Niño past, present and future

  • 26 Nov 2014, 18:00
  • Roz Pidcock

The Pacific weather phenomenon known as El Niño has attracted a lot of attention this year as forecasters have puzzled over its 'will it or won't it' behaviour.

In May, scientists were confidently predicting a  90 per cent chance of an El Niño materialising by the end of the year. But it's proved elusive, with the odds of even a weak event dropping to 58 per cent earlier this month.

El Niño brings extreme rainfall to some parts of the world and drought to others. So predicting when one will make an appearance and how big the effects will be is important.

A new study just published in Nature uses a diverse array of different data sources, from corals to computer modelling, to unravel what's been driving changes in El Niño over the past 21,000 years.

Pinning down this  enigmatic phenomenon is tricky, the study concludes. But there's reason to believe climate change could lead to stronger El Niño's in the future, say the scientists.

El Niño and climate-readiness

Every five years or so, a change in the winds causes a shift to warmer than normal ocean temperatures in the  equatorial Pacific Ocean - a phenomena known as El Niño.

Together, El Niño and its cooler counterpart La Niña are known as the El Niño Southern Oscillation (ENSO). Cycling between the two phases is responsible for much of the variation we see in global climate from one year to the next.

Knowing if and how climate change will affect El Niño and La Niña is an important scientific question, says Professor Kim Cobb, co-author on today's paper. She  told us recently:

"Preparing for large swings in temperature and rainfall is critical to adaptation strategies, especially if such variability will increase in the future."

In theory, human-caused warming could increase the strength of ENSO events, Cobb continues:

"It is important to remember that climate change is much more than "global warming" … Because ENSO involves feedbacks between the wind strength, ocean temperature, and circulation, a change in any related climate parameter would arguably have some effect on ENSO strength".

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Remote-controlled submarines reveal Antarctic sea ice is thicker than previously thought

  • 24 Nov 2014, 16:14
  • Robert McSweeney

WHOI UAV | Guy Williams

New research sees scientists using remote-controlled submarines to create 3D maps of Antarctic sea ice. And the results suggest sea ice is thicker than previously thought.

The area covered by Antarctic sea ice appears to be slightly growing each year, the reasons for which are proving hard to pin down. Today's research adds another dimension to unravelling the complex goings-on around the South Pole.

Measuring ice thickness isn't easy

Scientists have been monitoring changes at Earth's poles for decades now. But the harsh conditions of the Antarctic make it difficult to get good measurements of the sea ice that surrounds the vast continent.

How and why Antarctic sea ice thickness is changing "remains one of the great unknowns in the climate system," says Dr Ted Maksym of the Woods Hole Oceanographic Institution (WHOI) in Massachusetts.

While satellites are very good at measuring the extent, or area, of sea ice covering the ocean, they struggle when it comes to ice thickness. Satellite measurements can't distinguish between ice and the snow lying on top of it, which makes it harder for scientists get accurate readings of its true depth.

Scientists can also make estimates of thickness from visual observations or by drilling into the ice itself. But these approaches are hampered by thick sea ice during winter and spring, which prevents ships from accessing parts of the Antarctic coast.

To overcome these limitations, Dr Maksym and his colleagues deployed 'Autonomous Underwater Vehicles (AUVs)', which are specially-designed unmanned submarines that measure ice thickness to within 10 centimetres.

The data from these submarines, published in  Nature Geoscience, suggests that Antarctic sea ice is thicker than previously thought.

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World Bank: ending poverty might become impossible because of climate change

  • 24 Nov 2014, 13:54
  • Carbon Brief Staff

Lifting the world's poorest out of extreme poverty may become impossible because of climate change, according to the  World Bank's new Turn Down the Heat report.

It looks at the consequences of warming in three regions: the Middle East and North Africa, Latin America and the Caribbean, and eastern Europe and central Asia. The World Bank says these areas are already feeling the effects of 0.8 degrees of warming above pre-industrial temperatures.

If warming reaches four degrees by the end of the century, "unprecedented" heatwaves could affect the large majority of the land area of the Middle East, North Africa and Latin America in the coming decades. This new climate normal could  cut crop yields by up to 70 per cent while increasing flood risks by a third in some regions and pushing up the incidence of drought by a fifth in others.

The shocks and stresses to come could undermine poverty reduction, push new groups into  poverty, lead to  population migrations and even increase the  risk of conflict, the report says.

Poverty reduction

World Bank president Jim Yong Kim writes in a foreword to the report:

"Ending poverty, increasing global prosperity and reducing global inequality, already difficult, will be much harder with two degrees of warming, but at four degrees there is serious doubt whether these goals can be achieved at all."

Today, 1.2 of the world's 7 billion people live in extreme poverty.

Unfortunately the World Bank says some of the negative impacts of climate change may now be unavoidable because the world is "locked into" warming of close to 1.5 degrees above pre-industrial levels. Even very ambitious attempts to limit emissions  cannot change this.

But averting the worst projected climate impacts of a four degrees world remains technically, economically and politically feasible if global leaders are prepared to take tough choices now, Kim says.

Regional analysis

The report was prepared for the World Bank by the Potsdam Institute for Climate Impact Research and Climate Analytics, a Potsdam-based climate NGO and follows similar reports published in  2012 and  2013.

We've taken a look at the 300-page report's detailed findings for the Middle East, Latin America and Europe and central Asia, to see what challenges and changes a climate-changed future might hold.

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Tackle air pollution to kickstart climate action, says new study

  • 19 Nov 2014, 18:00
  • Roz Pidcock

Air pollution is a huge problem worldwide, killing millions of people each year. Further warming will only increase the size of the problem, according to a Nature article today.

It's time efforts to curb soot, ozone and other pollutants in the atmosphere got more attention at an international level, the researchers argue.

Getting serious about air pollution could provide the impetus needed to tackle climate change more effectively.

Airborne killers

Methane, ozone, nitrogen dioxide and soot (or black carbon) all contribute to poor air quality.

Air pollution is already the  leading environmental cause of ill-health, leading to about seven million premature deaths each year from respiratory and circulatory illnesses.

Earlier today, the European Council  ruled the UK must take urgent action to address dangerous levels of air pollution. A number of major cities, including London, are lagging behind targets to reduce nitrogen dioxide to legal limits by the January 2015 deadline.

The burden of ill-health is  likely to increase in cities by mid century, as air pollution interacts with further greenhouse gas warming, research shows.

Compounds Of Concern _Schmale

Impacts of common air pollutants for human health, the climate and agriculture. Source: Schmale et al. (2014)

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How small volcanic eruptions may have slowed surface temperature rise

  • 19 Nov 2014, 17:20
  • Robert McSweeney

Tungurahua eruption | Shutterstock

Scientists have been underestimating the influence of small volcanic eruptions on the climate system, a new study argues.

The findings could help explain why recent warming at the Earth's surface has been slower than in previous decades, the researchers say.

A cataclysmic event

In June 1991 Mount Pinatubo in the Philippines erupted, sending a cloud of ash, dust and sulphur dioxide 35 kilometers into the atmosphere.

That sulphur dioxide combined with oxygen and water to form sulphuric acid aerosols. These particles reflected sunlight and encouraged clouds to form, cooling parts of the world by up to 0.4°C for two years after the eruption.

Volcanic eruptions are rated from zero to eight on a scale of explosivity, measured by the amount of ash and debris they produce. The Pinatubo eruption was rated as a five, or 'cataclysmic'.

While the world hasn't seen such a huge volcanic eruption since, on average there is one small eruption somewhere in the world every week. A new study, published in Geophysical Research Letters, finds that these smaller eruptions may together have a bigger impact on global climate than previously thought.

Pinatubo _ash _plume _910612

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