Prospect of warmer winters doesn’t mean fewer deaths

Prospect of warmer winters doesn’t mean fewer deaths

New scientific study pours cold water on the theory that mortality rates will drop in winter months as the climate warms.

LONDON, 26 June, 2015 − Global warming is unlikely to mean that fewer people in northern latitudes will die from cold during the winter, according to a study by scientists in the US.

Despite arguments that an increase in death rates caused by global warming and increased summertime temperatures will be offset by a matching drop in mortality as winter temperatures also rise, the study cautions against assuming any such link as research suggests otherwise.

The study, carried out over several years, looked at temperature-related seasonal mortality rates, particularly among elder people, in a total of 39 cities – the majority in the US, and three in France.

It concludes: “Our findings suggest that reductions in cold-related mortality rates under a warming climate may be much smaller than some have assumed.”

The research, carried out by a team led by Professor Patrick Kinney, a specialist in public health at the Columbia University Earth Institute in the US, is published in the Environmental Research Letters journal.

Temperature range

“We found that excess winter mortality did not depend on seasonal temperature range and was no lower in warmer vs colder cities, suggesting that temperature is not a key driver of winter excess mortality,” the study says.

Although the researchers acknowledge that seasonal temperature patterns can have an effect on health, many other factors influence mortality rates in winter among elderly people.

Diseases such as influenza – often transmitted when younger generations of families meet up with their elders at family celebrations – play a far greater role in mortality than the cold.

“Most older people who die over the winter don’t die from cold – they die from complications related to ’flu and other respiratory diseases,”  Kinney says.

Most previous studies investigating the links between temperature rises and death rates have focused on the impact of summer heat.

“Most older people who die over the winter don’t die from cold – they die from complications
related to respiratory diseases”

A prolonged heatwave across Europe in 2003 – which many scientists say can be attributed to climate change – is believed to have caused between 30,000 and 50,000 deaths. Elderly people in urban areas – often left stranded in their baking apartment blocks – were particularly badly hit.

A lot of media attention has also been given recently to the high rates of death among migrant workers from Nepal working in high temperatures in Qatar and other countries in the Gulf region.

The Columbia study looked at winter death rates among elderly people in cities in different climate zones and with differing demographics – from Paris and New York to Miami and Marseilles.

Opposite effect

It found that most of the elderly people living in the cities from which data was gathered were not exposed to the winter cold for long periods as the majority had access to a warm indoor environment.

Kinney says that rather than decreasing mortality, warmer winters could have the opposite effect.

“We see mosquito-borne diseases emerging in new territories because warmer winter temperatures enable the insects to over-winter in more northerly regions,” he says.

“Warmer temperatures can also enable an insect-borne virus to replicate inside the insect vector to be transmitted and cause disease in a human or animal.

“Sadly, this research tells us that an increase in summer deaths due to climate change is unlikely to be counteracted by a reduction in winter deaths.” – Climate News Network

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India’s coastal villages map out disasters strategy

India’s coastal villages map out disasters strategy

The Indian Ocean can be an angry and sometimes lethal neighbour, but those who live beside it are now learning how to prepare for its next onslaught.

CHENNAI, 26 May, 2015 – It has been over a decade since the devastating tsunami struck southeast Asia, but the horrific memories remain as vivid as ever for people in the coastal villages of the south Indian state of Tamil Nadu.

Now, in the aftermath of the 2004 tsunami and also two cyclones, local people are benefiting from the Indian government’s encouragement of international co-operation in helping vulnerable communities, and have produced a hazard map as a precaution against future disasters.

Vikas Shankar, from the fishing village of Sulerikattukuppam, remembers clearly the moment the tsunami struck.“I was engrossed in playing cricket when I saw water entering the village,” he says. “I thought it was just another day when the sea poured in. Then, suddenly, I saw my mother caught in a whirlpool and realised something was seriously wrong.”

His mother, Tilakavathy, survived the tsunami’s fury, but recalls: “I thought this was really the end of the world.”

Completely destroyed

Amazingly, no one in the village died, but fishermen lost their gear and livelihoods, and many buildings close to the shore were completely destroyed.

The tsunami prompted Tilakavathy and her husband to decide not to send their sons to sea to earn a livelihood.

When Vikas, their youngest son, was old enough, he was sent instead to the local community college, built in 2011 by the state government to provide education and alternative livelihood opportunities for the fishing community.

The local people, recognising the need for disaster preparedness, are now involved in a programme that focuses on  developing communication tools for vulnerable communities and raising awareness of other disaster-related issues.

Krishnamurthy Ramasamy, professor of applied geology at the University of Madras, was formerly the principal of the community college. He says: “We realised the need for international collaboration to build a curriculum on disaster management and field-based learning activities.”

Kyoto University in Japan was one of the universities keen to work with him, and two Australian universities, Melbourne and Victoria, also joined in, helping with funds, curriculum development and exchange visits.

“We were taught how and why cyclones and tsunamis happen. It helped us to understand disasters in the first place.”

The college itself fostered community-based preparedness by offering disaster management as an optional subject, and by helping to set up a Local Residents’ Alliance (LRA) in 2013 to mobilise villagers. Most members of this group were parents of students from the college.

Vikas Shankar says: “In the class, we were taught how and why cyclones and tsunamis happen. It helped us to understand disasters in the first place.”

To learn about other people’s best practices, Professor Ramasamy visited communities along the Japanese coast, and there he made a significant discovery. He says: “The first thing I noticed in each village was the hazard map. I thought that we needed this too.”

Back at the college, work on hazard map preparation began, and the first step was students surveying their own villages to understand the geography better.

Teams went from house to house and marked all the huts in the village. They counted the number of people in the house, with details of numbers of women, children, old and disabled people living there. All this information went on the hazard map.

Miwa Abe, from the Centre for Policy Studies at Kumamoto University, Japan, who trained the Indian students, says: “A hazard mapping exercise with local people gives them an opportunity to know their village.

“It is not only about environmental conditions, but also human relationships, social networks, architectural conditions. Usually people do not think about their own area because it is too familiar to them.”

Evacuation routes

The teams also prepared evacuation routes, and, after six months of rigorous work, the students presented the final map to the local people.

Today, as one walks into the village, the first thing to catch the eye is the big blue hazard map board at its entrance. It shows the evacuation routes to be followed during disasters, and also the village’s population distribution − crucial information so that local people will know who to rescue first, and where they live.

The village’s approach is now being used as a case study in efforts to prepare community-based disaster management (CBDM) plans for the entire district, and eventually as a model for the state. The Tamil Nadu government has given land adjacent to the college to establish permanent infrastructure and to provide better facilities for the students.

Rajalakshmi Mahadevan, a fisherman’s daughter, says: “The evacuation map can be read by anyone, even a newcomer. Now we know which house to go to, who to evacuate first, and this has lifted the fear of disaster from local people’s minds.”– Climate News Network

  • Sharada Balasubramanian, an independent journalist from Tamil Nadu, India, writes on energy, agriculture and the environment. Email: sharadawrites@gmail.com; Twitter: @sharadawrites

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Rising temperatures mean fewer but fiercer hurricanes

Rising temperatures mean fewer but fiercer hurricanes

Climate change brings mixed prospects for people threatened by hurricanes: they are likely to occur less often, but when they do they will be even more destructive.

LONDON, 25 May, 2015 − Once again, scientists have confirmed the link between climate change and destructive hurricanes. The link is a simple one: a warmer world could mean fewer tropical storms, but those that arrive are likely to be more violent.

The conclusion is not new: other teams have already proposed that global warming linked to increases of carbon dioxide in the atmosphere as a consequence of fossil fuel combustion could drive tropical cyclones to higher latitudes and that the most destructive hurricanes could happen increasingly often. A British team has even linked better air quality – fewer sulphate aerosols and dust – to a greater probability of more violent winds.

But Nam-Young Kang, who now directs South Korea’s National Typhoon Center, and James Eisner, a geographer at Florida State University, set about a study of weather data and hurricane, cyclone and typhoon records between 1984 and 2012 to see if they could identify a pattern of change.

In the last 60 years or so, global average temperatures have risen, but are still less than 1°C above the average for the centuries before the Industrial Revolution. Hurricanes are linked to sea surface temperatures and the hurricane “season” does not start until ocean surface levels go beyond 26°C.

“We’re seeing fewer hurricanes, but the ones we do see are more intense. When one comes, all hell breaks loose”

The two scientists reckoned that even slightly higher average temperatures would mean more energy and therefore higher wind speeds at sea as well. They report in Nature Climate Change that they found what they were looking for: a pattern. On average, storm wind speeds had increased by 1.3 metres a second and there were 6.1 fewer tropical storms a year worldwide than there would have been if land and water temperatures had remained constant.

The research paper describes tropical cyclones – a term that for geographers also embraces Pacific typhoons and Atlantic hurricanes – as “perhaps the least welcomed natural phenomena on our planet” and points out that even well-developed, highly complex societies are exposed to them, and vulnerable. Superstorm Sandy, which began as an Atlantic hurricane, hit New York in 2012 with devastating consequences and even set the nation’s earthquake alarms ringing.

Professor Eisner has already established a link between temperatures and tornado hazard.  The new study delivers a statistical warning of a trade-off between frequency and strength offshore as well.“We’re seeing fewer hurricanes, but the ones we do see are more intense. When one comes, all hell breaks loose,” he said. − Climate News Network

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Green city offers clean alternative to tar sands boom

Green city offers clean alternative to tar sands boom

Canada has been dubbed an international disgrace for its climate change policies, but now one of its major cities is aiming to be the greenest in the world by 2020.

LONDON, 13 May, 2015 − In a country reckoned to have the worst climate policies in the industrialised world, one big city is setting out to defy central government and become 100% carbon neutral.

Vancouver, in British Columbia, Canada, wants to establish itself as “the greenest city in the world by 2020” by demonstrating that economic growth and the welfare of its citizens depends on developing renewables, rapid transit systems, and promoting cycling and walking to curb car use.

It is one of dozens of cities worldwide working towards improving the life of their citizens while reducing fossil fuel use, but it claims to have the most ambitious targets.

Many city administrations in Europe have the support of their governments, but in other countries − particularly Australia and Canada, where governments are actively promoting fossil fuels − cities are having to act alone.

A conference in Vancouver, attended by leaders from 45 countries, opens today to help the local government reach its goals.

Doubling green jobs

Among the “Green Vancouver” targets are doubling the number of green jobs in the city by 2020, from a 2010 baseline of 16,700, and making all new building in the city carbon neutral from 2020, while dramatically cutting emissions from existing buildings.

Progress towards meeting the city’s impressive list of targets includes reductions in air pollution, waste, water use and car journeys. Other aims are to provide a green space within five minutes walk for every citizen, planting thousands of trees, and growing food locally.

The city’s environment credentials go back to the 1970s, when there was a long battle to stop a freeway being built through the city. As a result, it is not possible to drive easily into the centre.

“The people who run Vancouver . . . are
business-savvy people who can see a vibrant green economy being a magnet for new business and forward-looking people”

Between 1996 and 2011, while the population in the city centre increased by 40%, there was a 25% decrease in the number of vehicle journeys, and a rise in the use of public transport, dedicated cycle routes and walkways.

Many other cities in the world that believe the way forward is to rid themselves of fossil fuels are attending to share experience – both of successes and failures.

That Vancouver is to become a centre of excellence is ironic, considering the fact that the federal government is seen as an international disgrace to the environment movement.

In 2011, it repudiated the Kyoto Protocol on emissions reduction targets, and has vigorously promoted the exploitation of oil from tar sands − the most polluting form of oil extraction, with high carbon dioxide emissions.

Power from renewables

In contrast, Vancouver, which has a population of 600,000, believes that all its power can come from renewables – although getting all heating and cooling and transport without using fossil fuels may take until 2040, depending on whether there is any help from central government.

One of the organisers of the conference, Shauna Sylvester, said: “When I first heard that Vancouver wanted to go 100% renewable, I thought it was a dream, but having looked at the possibilities I am a total convert.

“The people who run Vancouver do not have normal political affiliations. They are a bunch of business-savvy people who can see a vibrant green economy being a magnet for new business and forward-looking people. They are neither Labour nor Conservatives, but new progressives.”

Sylvester works at the Simon Fraser University Centre for Dialogue’s Renewable Cities Initiative, one of a number of organisations that aim to bring cities together to tackle climate change, because many local leaders believe that governments do not have the political will to do so.

Among those supporting the conference is the United Nations Environment Programme, which has its own campaign to green cities. − Climate News Network

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World needs early warning of climate-linked disasters

World needs early warning of climate-linked disasters

A leading French government minister says the number of natural disasters connected to climate change has doubled in two decades, and is urging a global early warning system.

LONDON, 15 March, 2015 − A senior French political leader, foreign minister Laurent Fabius, has told an international conference on how to reduce the risk from natural disasters that 70% of them are now linked to climate change, twice as many as twenty years ago.

Mr. Fabius is the incoming president of this year’s round of negotiations by member states of the UN climate change convention, to take place in Paris in December. He said disaster risk reduction and the struggle against climate change went hand in hand: “It is necessary to tackle these problems together and not separately.”

He was speaking against the background of two events which occurred thousands of miles apart on 14 March, linked by nothing except tragic coincidence.

In the Japanese city of Sendai the third UN world conference on disaster risk reduction began a five-day meeting. In the South Pacific Cyclone Pam brought death and devastation to the 83-island nation of Vanuatu on a scale seldom recorded in the region.

Vivien Maidaborn, executive director of Unicef New Zealand, said the disaster could prove one of the worst in Pacific history. “The sheer force of the storm, combined with communities just not set up to withstand it, could have devastating results for thousands across the region,” she said.

Hope shattered

A Unicef worker in Vanuatu described the cyclone as “15 to 30 minutes of absolute terror” for “everybody in this country” as it passed over.

The president of Vanuatu, Baldwin Lonsdale, told the UN meeting: “I am speaking with you today with a heart that is so heavy… All I can say is that our hope for prospering into the future has been shattered.”

The UN Secretary-General, Ban Ki-moon, opened the Sendai meeting, attended by 4,000 people from 186 countries, with a reminder that annual economic losses from natural disasters are now estimated to exceed US$ 300 billion annually.

He said: “We can watch that number grow as more people suffer. Or we can dramatically lower that figure and invest the savings in development. Six billion dollars allocated each year can result in savings of up to US$360 billion by 2030.”

A report released at the meeting, United for Disaster Resilience, prepared by insurance companies working with the UN Environment Programme’s Finance Initiative, said: “In the past decade, average economic losses from disasters were about US$190 billion per year, while average insured losses were about US$60 billion per year. This century, more than one million people have already lost their lives to disasters.”

Alert system

The UN Office for Disaster Risk Reduction, UNISDR, says global climate-related disasters between 1980 and 2011 included:

  • 3,455 floods
  • 2,689 storms
  • 470 droughts
  • 395 episodes of extreme temperature.

Mr Fabius said the creation of a worldwide early warning system for climate disasters could provide the most vulnerable countries, including small island developing states, with access to real-time weather and climate updates, information and communications technology, and with support for an SMS-based alert system. UNISDR’s PreventionWeb already links those working to protect communities against disaster risk.

Since the last such disaster risk conference in 2005, the UN says, at least 700,000 people have died, 1.7 billion more have been affected, and economic losses from major reported disasters total US$1.4 trillion.

The conference is working to prepare a new plan for reducing the risks of disasters. Margareta Wahlström, head of UNISDR, said: “After three years of consultation on a post-2015 framework which updates the current Hyogo Framework for Action, there is general agreement that we must move from managing disasters to managing disaster risk.” She said the framework would help to reduce existing levels of risk and avoid the creation of new ones. − Climate News Network

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Stalagmite links rain reduction to industrial revolution

Stalagmite links rain reduction to industrial revolution

Research shows the explosion of fossil fuel use to power the 19th-century industrial boom began the pattern of lower rainfall affecting the northern tropics. 

LONDON, 17 February, 2015 − Scientists have identified a human-induced cause of climate change. But this time it’s not carbon dioxide that’s the problem − it’s the factory and power station chimney pollutants that began to darken the skies during the industrial revolution.

Analysis of stalagmite samples taken from a cave in Belize, Central America, has revealed that aerosol emissions have led to a reduction of rainfall in the northern tropics during the 20th century.

In effect, the report in Nature Geoscience by lead author Harriet Ridley, of the Department of Earth Sciences at the University of Durham, UK, and international research colleagues invokes the first atmospheric crisis.

Acid rain

Before global warming because of greenhouse gases, and before ozone destruction caused by uncontrolled releases of chlorofluorocarbons, governments and environmentalists alike were concerned about a phenomenon known as acid rain.

So much sulphur and other industrial pollutants entered the atmosphere that raindrops became deliveries of very dilute sulphuric and nitric acid.

The damage to limestone buildings was visible everywhere, and there were concerns – much more difficult to establish – that acid rain was harming the northern European forests.

But even if the massive sulphate discharges of an industrialising world did not seriously damage vegetation, they certainly took a toll on urban human life in terms of respiratory diseases.

Clean-air legislation has reduced the hazard in Europe and North America, but it seems that sulphate aerosols have left their mark.

Researchers in a cave in Belize. Credit: Dr James Baldini/Durham University

Researchers in a cave in Belize.
Image: Dr James Baldini/Durham University

The Durham scientists reconstructed tropic rainfall patterns for the last 450 years from the analysis of stalagmite samples taken from a cave in Belize.

The pattern of precipitation revealed a substantial drying trend from 1850 onwards, and this coincided with a steady rise in sulphate aerosol pollution following the explosion of fossil fuel use that powered the Industrial Revolution.

They also identified nine short-lived drying spells in the northern tropics that followed a series of violent volcanic eruptions in the northern hemisphere. Volcanoes are a natural source of atmospheric sulphur.

Atmospheric pollution

The research confirms earlier suggestions that human atmospheric pollution sufficient to mask the sunlight and cool the upper atmosphere had begun to affect the summer monsoons of Asia, and at the same time stepped up river flow in northern Europe.

The change in radiation strength shifted the tropical rainfall belt, known as the intertropical convergence zone, towards the warmer southern hemisphere, which meant lower levels of precipitation in the northern tropics.

“The research presents strong evidence that industrial sulphate emissions have shifted this important rainfall belt, particularly over the last 100 years,” Dr Ridley says.

“Although warming due to man-made carbon dioxide emissions has been of global importance, the shifting of rain belts due to aerosol emissions is locally critical, as many regions of the world depend on this seasonal rainfall for agriculture.” – Climate News Network

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Climate data gives mixed message on storm forecasts

Climate data gives mixed message on storm forecasts

New research suggests that climate change won’t after all lead to more storms − but the bad ones could be even more devastating.

LONDON, 8 February, 2015 − Keep calm and hold on to your hat. The atmosphere will not become increasingly stormy as the planet warms and the climate changes.

The downside is that while the number of storms will probably remain unchanged, and weak storms could even become weaker, new research warns that the strongest storms could become significantly stronger.

For at least three decades, researchers have worked on the assumption that as the average energy of the atmosphere increased with warming, so would the potential for extremes of heat and drought, flood and cyclone, typhoon or hurricane.

Frederic Laliberté, of the University of Toronto in Canada, and atmospheric physicist colleagues don’t exactly disagree: they just took a closer at the way in which some things are likely to change.

Heat engine

They report in the journal Science that they considered the interplay of weather, moisture and temperature around the globe as an atmospheric heat engine – which it is – and compared it to a famous 19th-century theoretical model of energy and output known to engineers, physicists and meteorologists everywhere as the Carnot Cycle.

The engine works like this: air warmed by the sun moves across the ocean and takes up water through evaporation. The warmer the air, the more water it takes up. The air current gets to the Equator and then ascends through the atmosphere, cooling as it rises.

As the air cools, the burden of water condenses and releases heat. When enough heat is released, the air rises even further, pulling more air behind it to produce a thunderstorm.

A more vigorous water cycle could actually take yet more steam out of the atmospheric circulation.
The winds could run out of puff.

So the atmospheric engine’s output is the amount of heat and moisture it distributes between the Equator and the Poles.

“By viewing the atmospheric circulation as a heat engine, we were able to rely on the laws of thermodynamics to analyse how the circulation would change in a simulation of global warming,” Dr Laliberté said. “We used these laws to quantify how the increase in water vapour that would result from global warming would influence the strength of the atmospheric circulation.

To do this, they had to build on climate models, examine climate records for the last 30 years, and simulate the planet’s climate from 1982 to 2098.

Energy budget

They worked out that although the atmosphere is a machine, it isn’t a perfectly efficient one. At least a third of the atmosphere’s energy budget was dedicated simply to evaporating water and then dropping it as rain, and this drain on the overall energy available actually reduced the potential intensity of the winds around the planet, which is why the weather is, quite often, pleasant.

Like all science, the findings will be tested − first by other scientists and then by the planet itself. Time will tell. But the conclusion is that a more vigorous water cycle could actually take yet more steam out of the atmospheric circulation. The winds could run out of puff.

This wouldn’t work smoothly, though. Air masses that didn’t get to the top of the atmosphere would be weakened, but those that did get to the top would be more tempestuous.

“Powerful storms are strengthened at the expense of weaker storms,” Dr Laliberté says. “We believe atmospheric circulation will adapt to this less efficient form of heat transfer and we will see either fewer storms overall, or at least a weakening of the most common, weaker storms,” – Climate News Network

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Education protects best from climate risks

Education protects best from climate risks

Many of us accept that the world is warming but will not necessarily recognise that climate change caused by human activities is responsible. Social scientists say better education is the answer.

LONDON, 24 December, 2014 − Researchers in the US have confirmed the great global warming paradox: people recognise that climate may be changing and that the storms, floods or heat waves they experience are not normal − but whether they attribute the abnormalities to man-made climate change depends on their existing beliefs.

Political party identification, the researchers found, plays a role in these matters. Democrats generally believe in the idea of global warming, Republicans do not.

Aaron McCright, a sociologist at Michigan State University, and colleagues report in Nature Climate Change that they analysed Gallup Poll data from 2012 on the responses of 1,000 people to temperatures in their home states.

The winter of 2012 was the fourth warmest in the US since 1895. Around 80% of US citizens reported that winter temperatures were warmer than usual, and those polled by Gallup also recognised that the conditions were out of the ordinary.

But only 35% believed that the main cause of the abnormally high temperatures was global warming. “Many people had already made up their minds about global warming and this extreme weather was not going to change that,” said Dr McCright.

Mistaken assumption

“There has been a lot of talk among climate scientists, politicians and journalists that warmer winters like this would change people’s minds. The more people are exposed to climate change, the more they’ll be convinced. This study suggests that this is not the case.”

The research confirms a pattern, and others have already hypothesised that humans are not very enthusiastic about dealing with threats that lie some way in the future. The Michigan State researchers conclude that “actual temperature anomalies influence perceived warming but not attribution of such warmer-than-usual winter temperatures to global warming.

“Rather, the latter is influenced more by perceived scientific agreement; beliefs about the current onset, human cause, threat and seriousness of global warming; and political orientation. This is not surprising given the politicisation of climate science and the political polarisation on climate change beliefs in recent years.”

So the message is: personal experience might help spread support for the idea of adaptive measures, but it may not increase support for mitigation policies.

The North American warm winter of 2012 was only one of a string of extremes that indicate a pattern of change: the 2010 Russian heat wave, Superstorm Sandy on the US East Coast in 2012 and Typhoon Haiyan in the Pacific in 2013 were all natural disasters consistent, the researchers say, “with expectations for a warming world.”

Education matters most

Which is why Wolfgang Lutz of the International Institute for Applied Systems Analysis and colleagues argue in the journal Science that although huge sums of money will be spent on engineering adaptations to climate change, the urgent need is for universal education.

The researchers looked at recently-published analyses of disaster data from 167 countries in the last 40 years and found that making people aware of the hazards and their own vulnerability might do more than sea walls, dams, irrigation systems and other protective infrastructure.

For the researchers, knowledge is power. “Our research shows that education is more important than GDP in reducing mortality from natural disasters. We also demonstrated that under rapid development and educational expansion across the globe, disaster fatalities will be reduced,” said Raya Muttarak, one of the co-authors.

“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.” – Climate News Network

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Climate threatens striking change to US weather

Climate threatens striking change to US weather

Global warming is expected to have an explosive effect across America as scientists predict that there could be a 50% increase this century in the frequency of lightning strikes.

LONDON, 17 November, 2014 − Climate scientists foresee a brighter future for America − but no one will thank them for it, as global warming is expected to increase the total number of lightning strikes across the US this century by 50%.

David Romps, assistant professor in the Department of Earth and Planetary Science at the University of California, Berkeley, and colleagues report in Science journal that they looked at predictions of rainfall, snow, hail and cloud buoyancy in 11 different climate models. They concluded that the outcome could only be more atmospheric electrical action.

Right now, the continental US is hit about 25 million times a year by lightning.

But Dr Romps said: “With warming, thunderstorms become more explosive. This has to do with water vapour, which is the fuel for explosive deep convection in the atmosphere. Warming causes there to be more water vapour in the atmosphere, and if you have more fuel lying around, when you get ignition, it can go big time.”

More evaporation

Warmer weather means more evaporation. But higher temperatures also mean that the atmosphere’s capacity to hold water vapour increases as well, with a potential for more clouds, more flow of air, and more precipitation.

The volume of water hitting the ground – as hail, snow, sleet or rain – offers a measure of the convection properties of the atmosphere, and convection generates lightning.

Hundreds of people are struck by lightning each year, and scores are killed, but these remain a very small proportion of accidental deaths in any year. The real hazard might lie far from populated areas: half of all wildfires are caused by lightning strikes.

Lightning also generates more nitrous oxides in the atmosphere, which could also affect atmospheric chemistry. So it makes sense to know what to expect as the planet warms.

“We already know that . . . the more precipitation,
the more lightning”

The scientists examined US Weather Service data for 2011, and the counts from the National Lightning Detection Network, to see if they could confirm a link between cloud buoyancy and precipitation as a predictor of lightning. They also looked at data from balloon-borne instruments released every day in the US to measure the rate at which clouds rise.

As a result, they calculate that 77% of the variation in lightning strikes could be predicted from knowledge of the two conditions.

“Lightning is caused by charge separation within clouds, and to maximise charge separation you have to loft more water vapour and heavy ice particles into the atmosphere,” Dr Romps said. “We already know that the faster the updrafts, the more lightning, and the more precipitation, the more lightning.”

Potential energy

Their climate models predicted, on average, an 11% increase in convective available potential energy for every extra degree Celsius rise in average temperatures. They calculated that if average planetary temperatures were to rise by 4°C, the potential for lightning strikes would go up by 50%.

Their calculations are limited to the US mainland and may not apply equally to other parts of the planet. Overall conditions, and therefore the potential for thunderstorms, tend to vary widely.

But the continental US – the predictions do not include Hawaii or Alaska − is flanked by two oceans and with a subtropical sea to its south. It is distinguished by a sharp temperature gradient and dramatic topography, and is already a forge for fierce and destructive tornadoes, and a target for frequent hurricanes.

So the barometer remains set for future storms, with added lightning. – Climate News Network

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Ice loss sends Alaskan temperatures soaring

Ice loss sends Alaskan temperatures soaring

Scientists analysing more than three decades of weather data for the northern Alaska outpost of Barrow have linked an astonishing 7°C temperature rise to the decline in Arctic sea ice.

LONDON, 17 October, 2014 − If you doubt that parts of the planet really are warming, talk to residents of Barrow, the Alaskan town that is the most northerly settlement in the US.

In the last 34 years, the average October temperature in Barrow has risen by more than 7°C − an increase that, on its own, makes a mockery of international efforts to prevent global temperatures from rising more than 2°C above their pre-industrial level.

A study by scientists at the University of Alaska Fairbanks analysed several decades of weather information. These show that temperature trends are closely linked to sea ice concentrations, which have been recorded since 1979, when accurate satellite measurements began.

The study, published in the Open Atmospheric Science Journal, traces what has happened to average annual and monthly temperatures in Barrow from 1979 to 2012.

Most striking

In that period, the average annual temperature rose by 2.7°C. But the November increase was far higher − more than six degrees. And October was the most striking of all, with the month’s average temperature 7.2°C higher in 2012 than in 1979.

Gerd Wendler, the lead author of the study and a professor emeritus at the university’s International Arctic Research Center, said he was “astonished”. He told the Alaska Dispatch News: “I think I have never, anywhere, seen such a large increase in temperature over such a short period.”

The study shows that October is the month when sea ice loss in the Beaufort and Chukchi Seas, which border northern Alaska, has been highest. The authors say these falling ice levels over the Arctic Ocean after the maximum annual melt are the reason for the temperature rise. “You cannot explain it by anything else,” Wendler said.

They have ruled out the effects of sunlight because, by October, the sun is low in the sky over Barrow and, by late November, does not appear above the horizon.

Instead, they say, the north wind picks up stored heat from water that is no longer ice-covered in late autumn and releases it into the atmosphere.

At first sight, the team’s findings are remarkable, as Barrow’s 7.2°C rise in 34 years compares with a global average temperature increase over the past century of up to about 0.8°C. But what’s happening may be a little more complex.

Warming faster

The fact that temperatures in and around Barrow are rising fast is no surprise, as the Arctic itself is known to be warming faster than most of the rest of the world.

The Intergovernmental Panel on Climate Change says observed warming in parts of northern Alaska was up to 3°C from the early 1980s to the mid-2000s. It also concludes that about two-thirds of the last century’s global temperature increase has occurred since 1980.

But Barrow’s long-term temperature rise has not been uniform, the Fairbanks study says. Its analysis of weather records between 1921 and 2012 shows a much more modest average annual rise, of 1.51°C. In 2014, the city experienced the coolest summer day recorded − 14.5°C.

So one conclusion is to remember just how complex a system the climate is − and how even 34 years may be too short a time to allow for any certainty. − Climate News Network

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