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Warmer UK will face unequal death risk

April 2, 2014 in Extreme weather, Health, Heatwave, Human response, Temperature Increase, United Kingdom, Urban Heat

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Tower Bridge, the gateway to the East End of London which is likely to feel some of the strongest climate impacts Image: Myrabella / Wikimedia Commons / CC-BY-SA-3.0 & GFDL

Tower Bridge, the gateway to the East End of London which is likely to feel some of the strongest climate impacts
Image: Myrabella/Wikimedia Commons/CC-BY-SA-3.0 & GFDL

By Tim Radford

The impacts of climate change will strike unevenly, within countries as well as between them. People in poorer parts of  southern England will probably suffer most from rising heat.

LONDON, 2 April – Even in Britain, an island kingdom in a temperate zone, global warming will take its toll. And the greatest threat could be to the comfortable home counties of southern England which cluster round London.

According to research in Nature Climate Change, an average rise in summer temperatures of 2°C – and 2°C is the limit beyond which the world’s nations have agreed it would be unsafe to go – would mean around 1,550 extra deaths could be expected.

In the most vulnerable districts, the odds of dying increase by 10% for every 1°C rise in temperatures. In parts of northern England (the study was confined to England and Wales) there might be no extra deaths. But in southern England, which is often hit by extended periods of very warm weather, there was a significant rise in risk.

“It’s well known that warm weather can increase the risk of cardiovascular and respiratory deaths, especially in elderly people,” said James Bennett of Imperial College, London. “Climate change is expected to raise average temperatures and increase temperature vulnerability, so we can expect it to have effects on mortality even in countries like the UK with a temperate climate.”

As in all such forecasts, the extra deaths are notional: they are most likely to be in cases where people are already ill, or very old, and it would always be difficult to attribute any one death directly to a more than usually hot summer day. Britain, like France and other European countries, saw a sharp overall rise in mortality in 2003, when summertime temperatures soared and stayed high.

Bucking the trend

The value of such research is to help local clinics and hospitals to prepare for a greater number of emergencies. Between May and September during the decade 2001-2010, a total of 921,000 people died of cardio-respiratory causes, so the number of predicted extra deaths remains a small proportion of the normal toll.

More than half the deaths would be of people aged 85 and over, and almost two thirds would be women. The extra deaths would happen unevenly: half of all mortality would be in 95 out of 376 local authority districts in England and Wales.

The most vulnerable would be those who lived in already deprived boroughs in London such as Hackney and Tower Hamlets in the East End of the capital, and the chances of death would double on very hot days.

“The reasons for the uneven distribution of deaths in warm weather need to be studied”, said Majid Ezzati, a co-author. “We might expect people in areas that tend to be warmer would be more resilient because they adapt by installing air conditioning, for example. The results show that this isn’t the case in England and Wales.” - Climate News Network

Human activities ’caused record Oz heat’

March 24, 2014 in Australia, El Niño, Extreme weather, Forecasting, Heatwave, Ocean Warming, World Meteorological Organization

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Sanctuary for some: the summer of 2013 was a grim time for both humans and wildlife Image: By Австралиец via Wikimedia Commons

Sanctuary for some: the summer of 2013 was a grim time for both humans and wildlife
Image: By Австралиец via Wikimedia Commons

By Alex Kirby

Australia’s 2013 summer was the hottest on record only because of human influences on the climate,  meteorologists say. They report that people’s activities raised the likelihood of a record by about five times.

LONDON, 24 March – Australian researchers are in no doubt about what happened there last year. The country’s Bureau of Meteorology is a model of clarity: “2013 was Australia’s warmest year on record. Persistent and widespread warmth throughout the year led to record-breaking temperatures and several severe bushfires. Nationally-averaged rainfall was slightly below average.”

Now two Australian scientists say it is virtually certain that no records would have been broken had it not been for the influence on the climate of humans. They even put a figure on it: people, they say, raised the stakes about five times.

The World Meteorological Organization devotes a section in its report, WMO statement on the status of the global climate in 2013, to the scientists’ peer-reviewed case study, undertaken by a team at the ARC Centre of Excellence for Climate System Science at the University of Melbourne. It was adapted from an article originally published in the journal Geophysical Research Letters,

The study used nine global climate models to investigate whether changes in the probability of extreme Australian summer temperatures were due to human influences.

More frequent extremes ahead

It concluded: “Comparing climate model simulations with and without human factors shows that the record hot Australian summer of 2012/13 was about five times as likely as a result of human-induced influence on climate, and that the record hot calendar year of 2013 would have been virtually impossible without human contributions of heat-trapping gases, illustrating that some extreme events are becoming much more likely due to climate change.”

The report also strikes a warning note: “These types of extreme Australian summers become even more frequent in simulations of the future under further global warming.”.

It says last year was notable as well because it was marked by what scientists call “neutral to weak La Niña ENSO conditions”, which would normally be expected to produce cooler temperatures across Australia, not hotter. El Niño is characterized by unusually warm temperatures and La Niña by unusually cool ones in the equatorial Pacific.

Before 2013 six of the eight hottest Australian summers occurred during El Niño years. The WMO says natural ENSO variations are very unlikely to explain the record 2013 Australian heat.

“There is no standstill in global warming…The laws of physics are non-negotiable”

Introducng the report the WMO secretary-general, Michel Jarraud, said many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change. And he repeated his insistence that claims of a pause in climate change were mistaken.

There is no standstill in global warming. The warming of our oceans has accelerated, and at lower depths. More than 90% of the excess energy trapped by greenhouse gases is stored in the oceans.

“Levels of these greenhouse gases are at record levels, meaning that our atmosphere and oceans will continue to warm for centuries to come. The laws of physics are non-negotiable.”

The report says 13 of the 14 warmest years on record have all occurred during this century, and each of the last three decades has been warmer than the previous one, culminating with 2001-2010 as the warmest decade on record. It confirms that 2013 tied with 2007 as the sixth warmest year on record, continuing the long-term global warming trend.

Temperatures in many parts of the southern hemisphere were especially warm, and Australia was not the only country to feel the impact: Argentina had its second hottest year on record.- Climate News Network

Heat extremes threaten crop yields

March 21, 2014 in Agriculture, Climate risk, Drought, Extreme weather, Food security, Temperature Increase, Vegetation changes

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An undersized cob from a failed maize crop in Ghana's Upper West Region, which has suffered failed rains and rising temperatures Image: By CIAT (NP Ghana23_lo  Uploaded by mrjohncummings), via Wikimedia Commons

An undersized cob from a failed maize crop in Ghana which has suffered failed rains and rising temperatures
Image: By CIAT (NP Ghana23_lo Uploaded by mrjohncummings), via Wikimedia Commons

By Tim Radford

Yields of several major crops are likely to be seriously affected by rising temperatures, scientists say, with spells of extreme heat posing the greatest risk.

LONDON, 21 March – Rampant climate change driven by ever-rising levels of carbon dioxide in the atmosphere poses a serious threat to world food supply, according to a new study in Environmental Research Letters.

The hazard comes not from high average temperatures, but the likelihood of heat extremes at times when crops are most sensitive to stress. And the message is: those communities that rely on maize as a staple are more at risk than most.

Delphine Derying of the Tyndall Centre for Climate Change Research at the University of East Anglia in the UK and colleagues looked at one of the big puzzles of the coming decades: what will global warming do for crop yields?

It is not a simple question: climate change must mean more evaporation, more precipitation, longer growing seasons, more warmth, and higher levels of the carbon dioxide that plants exploit by photosynthesis (the process they use to convert light into chemical energy), so the consequence ought to be greater yields. But as every farmer knows, what matters most is the timing of all that warmth, rain, and those dry spells in which the harvest can ripen.

Danger in extremes

There is a second consideration. Climate is the sum of all events. Rather than a steady overall rise in daily temperatures, an increasing number of ever-larger regions are predicted to experience ever more intense extremes of heat, and sometimes cold. Plants can be very sensitive to extremes of heat at flowering time: if the thermometer goes up, the pollen becomes increasingly sterile and less seed is likely to be set. So an extended heat wave in the wrong season could be calamitous.

The Tyndall team included the assumption that nothing would be done about climate change – that is, that governments, industry and people would continue with a business-as-usual scenario. They then chose three well-studied and vital crops – spring wheat, maize and soybean – and tested predictions under 72 different climate change scenarios for the rest of this century.

They allowed for the already-established benign effects of carbon dioxide-driven warming, one of which is that plants can make more tissue and at the same time use water more efficiently, and therefore respond more effectively to drought conditions. They also looked for the outcomes in places where yields could be most vulnerable: for example, the North American corn belt.

Emissions cuts essential

What they found was that – if carbon dioxide fertilisation effects are not taken into account – then maize, wheat and soya yields are all likely to fall, in all five top-producing countries for each of these crops.

When they factored in the benefits of more CO2 in the atmosphere, the picture changed. There would be positive impacts on soya and wheat, but not on maize.

There is another proviso: so far, the benefits of extra CO2 have been confirmed in experimental plant laboratories. The experience in the fields 60 years in the future may be rather different. And in any case, these positive impacts could be severely offset by extremes of heat at the moment when the crops were most vulnerable, so overall, harvests remain at risk.

The best answer, the scientists argue, is to attempt to limit climate change. “Climate mitigation policy would help reduce risks of serious negative impacts on maize worldwide and reduce risks of extreme heat stress that threaten global crop production,” says Deryng. – Climate News Network

Climate technofixes ‘will not work’

March 7, 2014 in Adaptation, Deserts, Geoengineering, Marine ecology, Ocean acidification, Technology

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Plant forests in the desert? That would  alter ocean circulation Image: Jamou via Wikimedia Commons

Plant forests in the desert? That would alter ocean circulation
Image: Jamou via Wikimedia Commons

By Tim Radford

Hopes that we may be able to use geo-engineering to avert dangerous levels of climate change have been dashed by a German research team.

LONDON, 7 March – Global warming will be bad. Geoengineering could make it worse. Once again, a research team has considered all the benefits of climate technofix  – that is, deliberate steps to neutralize the consequences of unrestrained greenhouse gas emissions – and come to a grim conclusion.

At the best, any attempt to geo-engineer the changing climate back to its starting point would be relatively ineffective. At the worst, it would have “severe climatic side effects.”

David Keller and colleagues from the Helmholtz Centre for Ocean Research in Kiel, Germany and colleagues report in Nature Communications that they used an earth system model to simulate five very different strategies to reduce the rate of global warming and keep the climate from dramatic change.

Geo-engineering is a catch-all phrase for some very different approaches. One favoured and much-examined technique is to counter global warming by reducing the levels of sunlight that hit the planet’s surface, a technique called solar radiation management.

This approach has already been comprehensively dismissed by other studies, which have demonstrated that such an approach could change rainfall patterns or make conditions worse in arid zones such as the Sahel or just make things worse once the technology ceased.

But the Helmholtz team decided to look at the bigger picture: although climate scientists have repeatedly warned that the only safe answer is to reduce – and go on reducing – fossil fuel emissions, and although governments have acknowledged the urgency of the problem, very few really effective steps have been taken.

Varied options

So the technofix remains an option. How effective could it be? What could climate engineers do? There are plenty of powerful ideas. One of these is to exploit the appetite of green things for carbon dioxide: for instance, to irrigate the Australian and Sahara deserts and grow forests that will soak up more carbon.

Another is to nourish the ocean surface waters, by pumping deep, nutrient-rich bottom water to the surface to give algae a chance to bloom across the oceans. A third is to add lime to the oceans and chemically increase the uptake of carbon dioxide.

And then – still at sea – ships could spread that vital trace element iron across the ocean surfaces and give plankton a chance to bloom, grow, die and take all that carbon down to the seabed out of harm’s way.

And lastly, there is solar radiation management, either by pumping sulphate aerosols into the stratosphere, or putting reflectors in space: anything that reduces the sunlight levels a little could balance the impact of the greenhouse gas build-up.

The researchers simply contemplated the crude consequences of each step. They did not concern themselves with the economic, political and technological feasibility of each, nor the ethical questions. They just wanted to know whether any or all of these options could possibly work.

Limited potential

The answer, spelled out in 11 pages of close argument, is, basically, no. Could any of these limit warming? By about 8% perhaps: not nearly enough. Could all of them together have an effect? Even a combination of approaches could not stop global warming increasing by a lot more than 2°C by 2100 under the notorious “business as usual” scenario.

Would they have side effects? Yes, afforestation of deserts (if it could be done) would increase the local temperatures and increase freshwater flow and thus reduce the salinity of the oceans and change circulation patterns.

Ocean upwelling would increase the regions of the ocean with low oxygen – bad for living things – and precipitate rapid climate change if the upwelling stopped. Iron fertilization would increase ocean acidification and solar radiation management would do exactly what previous researchers have already said: change the weather patterns with alarming consequences and make things worse when the programme halts.

The message is: the most effective way to prevent further climate change is to limit carbon dioxide emissions.

“We find that even when applied continuously at scales as large as currently deemed possible, all methods are, individually, either relatively ineffective with limited warming reductions, or they have potentially severe side effects and cannot be stopped without causing rapid climate change,” the authors write.

“Our simulations suggest that the potential for these types of climate engineering to make up for failed mitigation may be very limited.” – Climate News Network

Hotter extremes belie warming ‘pause’

March 1, 2014 in El Niño, Ocean Warming, Trade Winds, Warming slowdown

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California's Death Valley is among the world's hottest places - but many are steadily getting hotter still Image: Pandat at de.wikipedia via Wikimedia Commons

California’s Death Valley is among the world’s hottest places – but many are steadily getting hotter still
Image: Pandat at de.wikipedia via Wikimedia Commons

By Tim Radford

Increasing and more frequent extremes of heat affecting wider regions, scientists say, are evidence that it is misleading to claim that climate change has paused.

LONDON, 1 March – If global warming has paused, nobody told the thermometer. Although global average temperature rises have not kept pace with greenhouse gas emissions in the last decade, the mercury has been higher than ever for longer than ever over increasingly larger areas of land, according to a new study in Nature Climate Change.

Sonia Seneviratne from the Swiss Federal Institute of Technology in Zurich and colleagues in Australia and Canada chose not to look at averages but at extremes of temperature. The scientists examined daytime extremes from 1979 onwards, and compared the temperatures of any particular day anywhere to an average of daily temperatures between 1979 and 2012, to identify the hottest 10%. Any region might normally expect 36.5 hottest days in a year; that is, hotter than the average.

Then they looked more closely at temperatures from 1997 to 2012. Regions that experienced 10, 30 or 50 extremely hot days above this average saw the greatest upward trends in extreme hot days over time – and over area. That is, not only were people experiencing greater heat extremes, but they were experiencing them over more days and over more extended regions.

And this consistent upward trend persisted right through the so-called “hiatus” of 1998 to 2012. The year 1998, at the time the hottest ever, coincided with a major El Niño event, the peak of a natural cycle of warmth and cooling in the Pacific.

Extreme extremes change most

Thereafter, although 13 of the 14 warmest-ever years have occurred this century, the rate of increase in warming as a global average has fallen. Climate sceptics used the trend to argue that global warming was an illusion, or part of a natural cycle. Dr Seneviratne and her colleagues do not see it that way.

“It quickly became clear the so-called ‘hiatus’ in global average temperatures did not stop the rise in the number, intensity and area of extremely hot days,” said Lisa Alexander of Australia’s Centre of Excellence for Climate System Science.

“Our research has found a steep upward tendency in the temperatures and number of extremely hot days over land and the area they impact, despite the complete absence of a strong El Niño.”

And her colleague Markus Donat added: “There has been no pause in the increase of warmest daily extremes over the land and the most extreme of the extreme conditions are showing the largest change.

“Another interesting aspect of our research was that those regions that normally saw 50 or more excessive hot days in a year saw the greatest increases in land area impact and the frequency of hot days. In short, the hottest extremes got hotter and the events happened more often.”

‘Illusory’ pause

However, perhaps because the world is mostly ocean, and the extremes have been measured over land, the average, year-on-year rises in temperatures have been lower in the last decade than in previous decades. There have been a number of inconclusive explanations for this phenomenon.

Cyclic changes in trade winds are one explanation; another is that the heat is there, but has been stored in the deep ocean, where measurements are not systematically taken. It’s there somewhere, waiting to be found.

And US scientists argue in the latest issue of the journal Science that the oceans may have an even bigger influence on climate than anybody foresaw, and that persistent cool conditions in the tropical Pacific may be behind what they call the “pause in global warming since 2000.”

But the latest Nature Climate Change paper puts the case that this pause or hiatus is illusory with – for a scientific paper – unusual clarity. “Based on existing observational evidence,” the authors say, “we highlight that the term pause, as applied to the recent evolution of global annual mean temperatures, is ill-chosen and even misleading in the context of climate change.

“Indeed, an apparently static global mean temperature can mask large trends in temperatures at both regional and seasonal scales.” – Climate News Network

Rising sea levels threaten Los Angeles

February 22, 2014 in Drought, Extreme weather, Sea level rise, Temperature Increase, USA

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Residents of the Cabrillo Marine Aquarium, one of the Los Angeles buildings at risk from sea level rise Image: By Jllm06 via Wikimedia Commons

Residents of the Cabrillo Marine Aquarium, one of the Los Angeles buildings at risk from sea level rise
Image: By Jllm06 via Wikimedia Commons

By Tim Radford

As much of California and the western US endures a severe drought, the city of Los Angeles is at increasing risk from rising sea levels, researchers say.

LONDON, 22 February – Los Angeles, City of the Angels in southern California, sits on a flat shelf of the Pacific coast of America, with a view of the sea. And if climate scientists are right, it could soon have an even closer view of the sea.

The city of more than 12 million people occupies 12,000 square kilometres of land, much of it no more than three metres above sea level. By 2050, rising sea levels could pose a threat to the infrastructure, museums and historic buildings of this great capital of entertainment, education, business, tourism and international trade, according to a new study by the University of Southern California.

“Some low-lying areas within the city’s jurisdiction, such as Venice Beach and some areas of Wilmington and San Pedro, are already vulnerable to flooding”, says Phyllis Grifman, lead author of the report, commissioned by the city and the USC Sea Grant Program.

“Identifying where flooding is already observed during periods of storms and high tides, and analyzing other areas where flooding is projected, are key elements to effective planning for the future.”

The city has already started to prepare for climate change: in June last year it published a report from the University of California Los Angeles on the pattern of snow fall and spring melt over recent decades and the ominous message for winter sports and summer water levels.

Double bind

Climate scientists expect the south-west of the US to become more arid as the century advances, and California has been in the grip of recent, unprecedented drought. But as glaciers melt and retreat, and the oceans warm and expand, the City of the Angels could find itself between the devil and the deep blue sea.

Sea levels are expected to rise somewhere between 0.6 metres and 1.7 metres by the close of the century. Peak tides and storm surges already present problems: as sea levels rise, these will become more damaging.

The drains that carry off its storm water and sewage, and deliver clean water from the mountains, could all be at risk from marine incursion. Floods and erosion could wear away the coast roads, and many museums and historic buildings, including the Cabrillo Marine Aquarium, could face damage. In 2012, Los Angeles attracted 41 million tourists who accounted for a total spending of more than $16 billion.

Some coastal communities, the report says “are home to highly vulnerable populations” already struggling with low incomes, linguistic isolation, older housing stock and lower education levels.

And a serious storm – the once-in-a-decade storm – could exact financial losses of $410 million if sea levels rise by half a metre. If they rise by about one and a half metres, the economic costs could tip more than $700 million. – Climate News Network

Arctic ‘is set to reach 13°C by 2100′

February 20, 2014 in Arctic, Climate risk, Feedbacks, Ice Loss, NOAA, Polar ice, Temperature Increase

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Iceberg in Rødefjord (Scoresby Sund), Greenland: Arctic sea ice volume has shrunk by 75% since the 1980s Image: Hannes Grobe 20:05, 16 December 2007 (UTC)

Iceberg in Rødefjord (Scoresby Sund), Greenland: Arctic sea ice volume has shrunk by 75% since the 1980s
Image: Hannes Grobe 20:05, 16 December 2007 (UTC) via Wikimedia Commons

By Alex Kirby

There is wide political agreement that global average temperatures should not rise more than 2°C above their level several centuries ago. The rise some scientists expect in the Arctic by 2100 is more than six times as great.

LONDON, 20 February – US scientists say that by the end of this century temperatures in the Arctic may for part of each year reach 13°C above pre-industrial levels. Global average temperatures have already risen by about 0.8°C over the level they were at in around 1750.

The Intergovernmental Panel on Climate Change said in its 2013 Fifth Assessment Report that it thought the probable global temperature rise by 2100 would be between 1.5 and 4°C under most scenarios. Most of the world’s governments have agreed the global rise should not be allowed to exceed a “safety level” of 2°C.

But James Overland, of the US National Oceanic and Atmospheric Administration, and colleagues, writing in the American Geophysical Union’s journal Earth’s Future, say average temperature projections show an Arctic-wide end of century increase of 13°C in the late autumn and 5°C in late spring for a business-as-usual emission scenario.

By contrast, a scenario based on climate mitigation would reduce these figures to 7°C and 3°C respectively. The team say they consider their estimates “realistic”, and they have used a large number of models in reaching them.

Ice fall

The Arctic is known to be warming fast, much faster than regions further south. The mean Arctic temperature is 1.5°C higher today than it was between 1971 and 2000, double the warming that occurred at lower latitudes during the same period.

The authors say Arctic sea ice volume has decreased by 75% since the 1980s. Reasons for the rapid warming include feedback processes linked to changes in albedo, which have caused a big drop in the ability of the Arctic’s snow and ice to reflect sunlight back into space.

As they melt they are replaced by darker rock and water, which, instead of reflecting the warmth away from the Earth, absorb it and help to raise the temperature. There are also changes taking place in ocean and land heat storage. These all help to amplify the effect of greenhouse gases in warming the Arctic.

Professor Overland and his colleagues say it is very likely that the Arctic Ocean will become nearly free of sea ice at some seasons of the year before 2050, and possibly within a decade or two. This in turn will further increase Arctic temperatures, economic access (for oil and gas exploitation and by shipping), and ecological shifts.

No agreement

The greenhouse gas emissions mitigation scenario the authors use (known as RCP4.5) assumes atmospheric concentrations of carbon dioxide (CO2) of about 538 parts per million (ppm). Before the Industrial Revolution concentrations were at about 280 ppm, and had changed little over many millennia. They are now at their highest in 15 million years, and rising at about 2 ppm annually, reaching almost 400 pp

Greenhouse gas emissions continue to rise, and so far world leaders have not managed to agree how to reduce them. Their efforts are now concentrated on next year’s UN climate change convention meeting, to be held in the French capital, Paris.

Professor Overland and his colleagues conclude that major changes in the Arctic climate are “very likely” over the decades until 2040, including “several additional months of open water in the Arctic Ocean, ever earlier snow melt, further loss of permafrost, increased economic access, and dramatic impacts on ecological systems.”

They say the large difference in surface air temperatures in the Arctic at the end of the century, which they are confident will happen, “makes a strong case to begin mitigation activities for greenhouse gases”. – Climate News Network

Cities’ twin heat problems face relief

February 15, 2014 in Population, Temperature Increase, Urban Heat

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A hot day in Beijing's Tiananmen Square: Cities are usually hotter than the countryside Image: Tactesh882 via Wikimedia Commons

A hot day in Beijing’s Tiananmen Square: Cities are usually hotter than the countryside
Image: Tactesh882 via Wikimedia Commons

By Tim Radford

Climate change aside, cities tend to be warmer than the surrounding ciuntryside. Now researchers in the US have found ways that may lessen the effects of both problems.

LONDON, 15 February – Even without global warming, atmospheric temperatures are likely to rise later in the century: the expansion of the cities will see to that.

Climate scientists and meteorologists long ago recognised the “heat island” effect created by the cities, and made sure routine measurements were not distorted by urban sprawl. But Matei Georgescu of Arizona State University and colleagues think that as populations grow, and cities begin to spread, temperatures will rise anyway.

So, they report in the Proceedings of the National Academy of Sciences, they have tested a few strategies to mitigate the rise of city temperatures and perhaps at the same time turn down the rate of rise in greenhouse temperatures as well.

The argument goes like this: roofs, paved roads, pipes, wiring, traffic, central heating and air conditioning, industry and commerce and other such urban trappings could raise temperatures by 1°C to 2°C.

And cities are certain to expand: the population of the US is expected to grow to somewhere between 422 million to 690 million by 2050, with up to 260,000 square kilometers of land newly covered by roofs and roads.

Winter problems

Global urban area is expected to grow by 185% by 2030; much of that will be in China and India. In that same time Africa could see the greatest proportional increase: African cities are expected to expand sixfold.

“Urban expansion within these areas will almost certainly be highly concentrated, exposing highly vulnerable populations to land use-driven climate change,” the authors say.

So the researchers started to think about some simple changes that could reduce urban temperatures. The first conclusion was that adaptations needed to be tailored to local climates and needs.

One simple answer is the “cool roof” – paint it white so it reflects the sunlight, and in California’s Central Valley, at least, the temperature levels fall. In other simulated environments, the measure didn’t work so well: reflective roofs lowered the temperature too well in winter, necessitating extra investment in heating fuels.

“Green” roofs, covered with turf or planted with transpiring foliage, were more effective in other urban climates: these highly transpiring structures did not compromise summertime energy savings by demanding additional energy in winter.

Horses for courses

With judicious planning and careful choice of design, it could be possible not only to counteract urban growth temperature increases but even offset the effect of greenhouse gas warming as well, not just over the cities, but beyond the cities as well.

But there was no simple, one-size-fits-all answer. Geography played an important role in any such calculations.

The study delivered unexpected results. In Florida, the team’s simulations significantly reduced rainfall, a result that would have implications for water supply and local ecosystems.

“For Florida, cool roofs may not be the optimal way to battle the urban heat island because of these unintended consequences,” Georgescu said.

“We simply wanted to get all these technologies on a level playing field and draw out the issues associated with each one, across place and across time.” - Climate News Network

There’s no warming standstill says WMO

February 5, 2014 in Climate risk, El Niño, Temperature Increase, Warming slowdown

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Aerial fire-fighting in Australia, which in 2013 had its hottest year on record Image: Bidgee via Wikimedia Commons

Aerial fire-fighting in Australia, which in 2013 had its hottest year on record
Image: Bidgee via Wikimedia Commons

By Alex Kirby

The head of the World Meteorological Organization tells Climate News Network there is no standstill in global warming, which is on course to continue for generations to come.

LONDON, 5 February – The planet is continuing to warm, with implications for generations ahead, and temperatures are set to rise far into the future, the World Meteorological Organization (WMO) reports.

It says 2013 was among the ten warmest years since modern records began in 1850, equalling 2007 as the sixth warmest year, with a global land and ocean surface temperature 0.50°C above the 1961–1990 average and 0.03°C higher than the most recent 2001–2010 average.

Thirteen of the 14 warmest years on record have all occurred in this century. The warmest years on record are 2010 and 2005, with global temperatures about 0.55 °C above the long-term average, followed by 1998, which also had an exceptionally strong El Niño event.

El Niño events (which intensify warming) and cooling La Niñas are major drivers of natural climate variability. Neither occurred during 2013, which was warmer than 2011 or 2012, when La Niña exerted its cooling influence. 2013 was among the four warmest neutral years recorded, when neither El Niño nor La Niña affected temperatures.

“The global temperature for the year 2013 is consistent with the long-term warming trend”, said WMO Secretary-General Michel Jarraud. “The rate of warming is not uniform but the underlying trend is undeniable. Given the record amounts of greenhouse gases in our atmosphere, global temperatures will continue to rise for generations to come.

“Which standstill? The coldest year since 2001 is warmer than any year before 1998″

“Our action – or inaction – to curb emissions of carbon dioxide and other heat-trapping gases will shape the state of our planet for our children, grandchildren and great-grandchildren”, Mr Jarraud said.

Asked by Climate News Network how WMO regarded claims by some critics that there has been a “global warming standstill since 1997″, Mr Jarraud said: “Which standstill? The coldest year since 2001 is warmer than any year before 1998.

“Each decade is warmer than the previous one. There is global variability from year to year. You have to look at the longer period. If you do that, then the message is beyond any doubt…Despite the fact that there was no El Niño in 2013, it was still the sixth warmest year. This is significant.”

The WMO says surface temperature is just part of a much wider picture of climate change. “More than 90% of the excess heat being caused by human activities is being absorbed by the ocean“, it says.

It has released the temperature data in advance of its full Statement on the Status of the Climate in 2013, to be published in March. This will give more details of regional temperatures and other indicators.

Consistent findings

In contrast with 2012, when the US in particular experienced record high annual temperatures, the warmth in 2013 was most extreme in Australia, which had its hottest year on record.

WMO’s global temperature analysis is based mainly on three independent and complementary datasets. One is maintained by two UK centres, the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia. The other two are based in the US: NOAA’s National Climatic Data Center, and the Goddard Institute for Space Studies (GISS), operated by NASA.

Each dataset uses slightly different methods of calculation and so each gave 2013 a different temperature ranking, but they were consistent on the year-by-year changes and the longer warming trends globally.

WMO also uses reanalysis-based data from the European Centre for Medium-Range Weather Forecasts (ECMWF), which showed annual global land and ocean temperature to be the fourth highest on record. – Climate News Network

Warmth spurs plants to move or bloom earlier

February 2, 2014 in Adaptation, Phenology, Temperature Increase, United Kingdom, Vegetation changes

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Sign of spring: Bluebells will increasingly need to choose a strategy to let themcope with awarmer planet Image: Nana B Agyei via Wikimedia Commons

Sign of spring: Bluebells will increasingly need to choose a strategy to let them cope with a warmer planet
Image: Nana B Agyei via Wikimedia Commons

By Tim Radford

Plants reacting to climate change have two strategies to deal with increasing warmth: they escape the heat either by moving towards the poles, or by flowering sooner.

LONDON, 2 February – Scientists are one step closer to solving one of the puzzles of the natural world’s response to climate change: why one species migrates and another does not.

Tatsuya Amano of the University of Cambridge in the UK and colleagues report in the Proceedings of the Royal Society B that there could be a relatively simple explanation, especially for plant behaviour. Those that can make new colonies move north (or south, in the southern hemisphere) to take advantage of changing temperature regimes. Others simply shift the time zone: they flower earlier.

The response of flora and fauna to climate change is not a simple one: all sorts of influences are at play, including changes in habitat and in farming methods, in competition from alien introductions, and in the introduction of new kinds of predator.

But over the decades, scientists have been able to measure distinctive shifts. In alpine Switzerland, plants, butterflies and birds were all observed to move uphill  as temperatures shifted through the decades. In Britain, some butterfly populations
were observed to extend their range northwards while others were less able to take advantage of the opportunity to exploit new territory.

Dr Amano and his partners – from Britain, Poland and Germany – looked at a long sequence of historical records to explore the responses of plants. The theory is that over evolutionary time, each species finds a favoured “niche” that suits it best, and occupies it.

As climate conditions change, so should the ideal niche, and plants should shift their ground or respond in some other way. All the research requires is a lot of data, collected over hundreds of years.

General principle

“Britain is the ideal study system for this purpose because historical changes in first flowering dates have been estimated for 405 plant species by applying a hierarchical model to almost 400,000 observation records throughout the country”, say the authors, “and records on spatial distribution are available for 6,669 higher plant taxa throughout Britain at two census periods” (a taxon is a group of natural populations judged by taxonomists to constitute a unit).

They were able to work from 395,466 records of 405 flowering species collected between 1753 and 2009, held by the UK Phenology Network.They also had access to the oldest set of weather records on the planet, the Central England Temperature series, recording daily temperatures since 1772.

By using sophisticated mathematical techniques and a lot of data, the team were able to settle at least one very general principle: if a plant could not take advantage of warmer weather by flowering earlier then there was a greater likelihood that it would shift its range northwards. And there was a complementary relationship: if a plant could not change its ground, it changed its phenology.

The finding gives conservation scientists some more general principles to apply. It also reveals some of the characteristics that might indicate how a species might be predicted to respond. The word “might” is important here. Their findings, the authors say, “need to be carefully interpreted, as our models generally had a low explanatory power.” – Climate News Network