Monday, June 29, 2015

Scientists have discovered how dramatic climate change in the Southern Sahara reduced the largest freshwater lake on Earth to the desert dunes we see today in just a few hundred years

Alpha Galileo via Royal Halloway, University of London: Researchers from Royal Holloway, Birkbeck and Kings College, University of London used satellite images to map abandoned shore lines around Palaeolake Mega-Chad, and analysed sediments to calculate the age of these shore lines, producing a lake level history spanning the last 15,000 years.

At its peak around 6,000 years ago, Palaeolake Mega-Chad was the largest freshwater lake on Earth, with an area of 360,000 km2. Now today’s Lake Chad is reduced to a fraction of that size, at only 355 km2. The drying of Lake Mega-Chad reveals a story of dramatic climate change in the southern Sahara, with a rapid change from a giant lake to desert dunes and dust, due to changes in rainfall from the West African Monsoon. The research, published this week in the journal Proceedings of the National Academy of Sciences of the United States of America confirms earlier suggestions that the climate change was abrupt, with the southern Sahara drying in just a few hundred years.

Part of the Palaeolake Mega-Chad basin that has dried completely is the Bodélé depression, which lies in remote northern Chad. The Bodélé depression is the World’s single greatest source of atmospheric dust, with dust being blown across the Atlantic to South America, where it is believed to be helping to maintain the fertility of tropical rainforests. However, the University of London team’s research shows that a small lake persisted in the Bodélé depression until about 1,000 years ago. This lake covered the parts of the Bodélé depression which currently produce most dust, limiting the dust potential until recent times.

“The Amazon tropical forest is like a giant hanging basket” explains Dr Simon Armitage from the Department of Geography at Royal Holloway. “In a hanging basket, daily watering quickly washes soluble nutrients out of the soil, and these need to be replaced using fertiliser if the plants are to survive. Similarly, heavy washout of soluble minerals from the Amazon basin means that an external source of nutrients must be maintaining soil fertility. As the World’s most vigorous dust source, the Bodélé depression has often been cited as a likely source of these nutrients, but our findings indicate that this can only be true for the last 1,000 years,” he added.

NASA image of a dust storm near what's left of Lake Chad

Sunday, June 28, 2015

Asia-Pacific trains for disruptions in climate

Business World Online: The US government is setting up a course to train officials in the Asia-Pacific region in the basics of preparing and financing projects to help communities weather climate change, experts from the US Agency for International Development (USAID) said on Friday.

Private citizens and military personnel join hands as they volunteer to re-pack relief goods composed of food clothing and other basic necessities at the Department of Social Welfare and development headquarters in Pasay, Philippines November 18, 2013

Financing needs for climate change adaptation -- efforts to adjust to extreme weather and rising seas -- are estimated at tens of billions of dollars per year in developing countries. But in 2013, only $25 billion in public resources went to adaptation around the world. Rich countries have promised to mobilize an annual $100 billion by 2020 to help poor nations adapt to climate change and develop their economies on a low-carbon path.

The key challenge is channelling money from large donors to small, poor communities that are hardest hit by climate-related disasters, experts said in an online discussion supported by the Asia Pacific Adaptation Network.

Most international funders cannot lend directly to smaller communities, and have to go through national agencies, such as finance ministries, said Peter King who works on USAID’s Bangkok-based Adapt Asia-Pacific project. “Not only do (local authorities) have problems in implementing projects,” Mr. King said. “In our experience they have difficulty in designing projects too.”...

Typhoon Bolaven in Okinawa, 2012, US Marine Corps photo

Sunday, June 21, 2015

Jet contrails affect surface temperatures

Space Daily: High in the sky where the cirrus ice crystal clouds form, jet contrails draw their crisscross patterns. Now researchers have found that these elevated ice cloud trails can influence temperatures on the ground and affect local climate, according to a team of Penn State geographers.

"Research done regarding September 2001, during the three days following 9-11 when no commercial jets were in the sky, suggested that contrails had an effect," said Andrew M. Carleton, professor of geography. "But that was only three days. We needed to look longer, while jets were in the air, to determine the real impact of contrails on temperature and in terms of climate." "Certain regions of the U.S. have more favorable atmospheric conditions for contrails than others, " said Jase Bernhardt, graduate student in geography.

For contrails to form, the atmosphere at the level the jet is flying must be cold enough that the moisture from the jet exhaust freezes into ice crystals. There also must be enough moisture in the air that the clouds that form remain in the sky for at least a few hours as persisting contrails.

Bernhardt and Carleton looked at temperature observations made at weather station sites in two areas of the U.S., one in the South in January and the other in the Midwest in April. They paired daily temperature data at each contrail site with a non-contrail site that broadly matched in land use-land cover, soil moisture and air mass conditions. The contrail data, derived from satellite imagery, were of persisting contrail outbreaks. The researchers reported their results in a recent issue of the International Journal of Climatology.

They found that contrails depress the difference between daytime and nighttime temperatures, typically decreasing the maximum temperature and raising the minimum temperature. In this respect, the contrail clouds mimic the effect of ordinary clouds....

US Air Force photo

Ghana destroys hundreds of homes in capital in bid to prevent floods

Matthew Mpoke Bigg in Reuters: Bulldozers razed hundreds of homes and businesses in the poor Sodom and Gomorrah neighborhood of Ghana's capital on Saturday so the authorities can start widening a lagoon to prevent a repeat of this month's deadly floods.

Some residents said security forces sprayed them with tear gas after they threw stones to protect their livelihoods from the bulldozers. By evening, thousands were stranded in the rain amid rubble and household goods strewn for more than a mile.

"What they have done is not good for us because this is where some of us work and take care of our families," said scrap metal merchant Muhammed Abdul Karim as he surveyed the wreckage of his shack and the motorized tricycle he uses to haul iron.

Flood control has become an urgent problem for President John Mahama's government since more than 50 people drowned in torrents caused by blocked drains on June 3-4, a tragedy that exposed the country's creaking infrastructure.

The same night 96 people sheltering from the floods at a downtown gas station died when it exploded in the worst disaster in decades in the West African country.

The incidents add to the difficulties facing President Mahama 18 months before the government faces voters in what is likely to be a tight election in one of Africa's more stable democracies....

Jamestown in Accra, shot by Adotey Hoffman, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Risk of major sea level rise in Northern Europe

A press release from Niels Bohr Institute: Global warming leads to the ice sheets on land melting and flowing into the sea, which consequently rises. New calculations by researchers from the Niels Bohr Institute show that the sea level in Northern Europe may rise more than previously thought. There is a significant risk that the seas around Scandinavia, England, the Netherlands and northern Germany will rise by up to about 1½ meters in this century. The results are published in a special issue of the scientific journal Climate Research.

Sea level rise is a significant threat to the world’s coastal areas, but the threat is not the same everywhere on Earth – it depends on many regional factors. “Even though the oceans are rising, they do not rise evenly across the globe. This is partly due to regional changes in the gravitational field and land uplift,” explains Aslak Grinsted, associate professor at the Centre for Ice and Climate at the Niels Bohr Institute, University of Copenhagen.

He explains that gravity over the surface of the land and sea varies due to differences in the subsurface and surroundings – the greater the mass, the greater the gravity. The enormous ice sheet on Greenland attracts the sea, which consequently becomes higher around Greenland. When the ice sheet melts and flows out to sea as water, this attraction is reduced and even though more water has entered the sea, the sea level around Greenland would fall.

...Another very important effect for Northern Europe is that during the ice age we had a thick ice sheet that weighted down the land. When the weight disappears, then the land rises and even though it has been more than 10,000 years since the ice disappeared, the land is still rising. The calculations show that in the Gulf of Bothnia the land is still rising faster than the expected sea level rise....

...“Based on the UN climate panel’s report on sea level rise, supplemented with an expert elicitation about the melting of the ice sheets, for example,how fast the ice on Greenland and Antarctica will melt while considering the regional changes in the gravitational field and land uplift, we have calculated how much the sea will rise in Northern Europe,” explains Aslak Grinsted.

,,,The calculations show that there is a real risk that what have been regarded as high scenarios in the Netherlands and England will be surpassed....

Lemvig on the Danish coast, shot by Anigif, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Thursday, June 18, 2015

'Once in generation' chance to reform climate insurance

Mark KInver at BBC: Policymakers have a "once in a generation" chance to reform insurance to help those most at risk from climate change impacts, say researchers.

A Cambridge University team is calling for insurance reforms to be explicitly mentioned in the UN's forthcoming Sustainable Development Goals. They outlined their proposals at an insurance summit at the UN, New York.

G7 leaders recently pledged to help 400 million people have access to insurance cover against extreme weather events. The researchers produced a policy brief that was presented to the global gathering at the UN headquarters.

"My role was to highlight the policy implications of having insurance at the centre of requirements to protect exposed populations," explained policy-brief author Ana Gonzalez Peleaz, a fellow from the Cambridge Institute for Sustainability Leadership.

"The lack of effective insurance regulation is a problem for accessing insurance across all parts of society." For example, she told BBC News, there were a number of nations that did not allow mutual insurance companies - these are companies that are wholly owned by policyholders, with the sole purpose of providing cover for its members and policyholders.

"The lack of regulation can have devastating consequences for customer protection and also insurers cannot really grow if the regulatory environment is not supportive."...

NOAA image of a tropical cyclone's eyewall 

Wednesday, June 17, 2015

Groundwater resources draining fast, NASA data show

Timothy Cama in the Hill: Humans are depleting a large portion of the world’s groundwater resources, and they are not being naturally refilled, researchers said. The scientists at the University of California Irvine used data from National Aeronautics and Space Administration (NASA) satellites to determine drainage of the world’s largest groundwater aquifers in recent years.

They found that a third of the 37 major aquifers were either worse off in 2013 than in 2003 or were highly stressed. “Available physical and chemical measurements are simply insufficient,” Jay Famiglietti, the principal researcher on the project, said in a Tuesday statement. Famiglietti is both a UC Irvine professor and the top water scientist at NASA’s Jet Propulsion Laboratory.

“Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left,” he said.

The paper was published Tuesday in the journal Water Resources Research. It is the first to use data from NASA’s Gravity Recovery and Climate Experiment, or GRACE, satellite system, which detects changes in Earth’s gravity that can show groundwater levels.

It found that the most stressed aquifers were in extreme dry areas, whose residents and businesses have leaned most heavily on groundwater....

A bore well pump in India, shot by ABHIJEET, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Monday, June 15, 2015

Drought may hit rural Indian economy, aggravating poverty

Mayank Bhardwaj in Reuters: India's farm economy could contract this fiscal year for the first time in over a decade because of drought, threatening Prime Minister Narendra Modi's drive to lift millions in the countryside out of poverty and bolster his party's support.

Roughly half of India's farmland lacks irrigation and relies on monsoon rain, but this year's rainfall is officially forecast to be only 88 percent of the long-term average and, for the first time in nearly three decades, farmers face a second straight year of drought or drought-like conditions.

That comes on top of a crash in commodity prices, unseasonable rain earlier this year and delayed sowing late last year because of scanty monsoon rain.

"Farmers are already reeling under heavy losses ... and now they don't have money to irrigate their fields or use an optimum level of inputs like fertiliser," said Ashok Gulati, an agricultural economist who formerly advised the government on crop support prices...

A 2012 drought in Karnataka, shot by Pushkarv, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Saturday, June 13, 2015

Flash flood risks increase as storm peak downpours intensify

EurekAlert via the University of New South Wales: Patterns of peak rainfall during storms will intensify as the climate changes and temperatures warm, leading to increased flash flood risks in Australia's urban catchments, new UNSW Australia research suggests.

Civil engineers from the UNSW Water Research Centre have analysed close to 40,000 storms across Australia spanning 30 years and have found warming temperatures are dramatically disrupting rainfall patterns, even within storm events.

Essentially, the most intense downpours are getting more extreme at warmer temperatures, dumping larger volumes of water over less time, while the least intense periods of precipitation are getting weaker. If this trend continues with future warming, the risk of flooding due to short-term extreme bursts of rainfall could increase even if the overall volume of rain during storms remains the same. The findings were published today in the journal Nature Geoscience.

"These more intense patterns are leading to more destructive storms, which can significantly influence the severity of flood flows," says lead author and PhD candidate Conrad Wasko, from the UNSW School of Civil and Environmental Engineering. "The climate zones we studied in Australia are representative of most global climates, so it's very likely these same trends will be observed around the world."

Previous studies have looked at rainfall volumes over the total duration of storms, but this latest UNSW study is the first to look at temporal rainfall patterns within storms. Australian Bureau of Meteorology data from 79 locations across the country were used instead of computer simulations....

Photo by Shootthedevgru,Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Rising global temperatures will have little effect on boreal peatlands

Jeff Sternsland at the University of South Carolina:
To some scientists studying climate change, boreal peatlands are considered a potential ticking time bomb. With huge stores of carbon in peat, the fear is that rising global temperatures could cause the release of massive amounts of CO2 from the peatlands into the atmosphere—essentially creating a greenhouse gas feedback loop.

A new study by researchers at the University of South Carolina and University of California Los Angeles challenges that notion, and demonstrates that the effect of temperature increases on peat storage could be minor. Funded by the National Science Foundation (NSF) and published in “Global Biogeochemical Cycles,” the study instead points to the length of time peat is exposed to oxygen as a much more important factor in how it releases carbon into the atmosphere.

The researchers used the biochemical composition of a peat core collected from the James Bay Lowland in Canada to assess the historical relationship between climate and the extent of peat decomposition. The core is a record of peat accumulation over the last 7,500 years and contains two intervals (the Medieval Climate Anomaly and the Holocene Thermal Maximum) when temperatures were about 2°C warmer than normal, providing a natural analogue for modern warming.

However, peat formed during these warm intervals was not extensively decomposed compared to peat formed during cooler periods. Instead, the most extensive decomposition coincided with drier conditions and longer oxygen exposure time during peat formation. This indicates oxygen exposure time was the primary control on peat decomposition, while temperature was of secondary importance. This was supported by comparing the extent of decomposition along a climate transect in the West Siberian Lowland, Russia. Cores from the northern end of the transect, which experienced longer oxygen exposure times, were more decomposed than cores from the south, which formed under warmer temperatures...

Sunset on the tundra, shot by Paul Gierszewski, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Even longer and stronger heat waves predicted for India

Max Martin in the New Indian Express: With more than 2,300 dead in extremely hot weather across India, a recent Indian Institute of Technology-Bombay (IIT-B) study predicts more intense and longer heat waves, more often and earlier in the year in future. In a changing climate, newer areas, including large swathes of southern India and both coasts will be severely hit, resulting in more heat stress and deaths, said the study, published in the journal Regional Environmental Change.

“From climate model projections, we have pointed out that there is a possibility of high occurrences of heat waves in South India in future,” says Subimal Ghosh, associate professor at the Department of Civil Engineering, IIT-B, and one of the paper’s authors.

Such a forecast is in line with global and Indian studies. Other recent assessments have predicted that intense heat waves will grow with rising global temperatures, up by 0.9 degrees Celsius since the start of the 20th century.

The Intergovernmental Panel on Climate Change (IPCC) records that from 1906 to 2005, the mean annual global surface-air temperature increased by about 0.74 degrees (land-surface air temperature increases more than sea-surface temperature). As a result, there will be significant changes in the frequency and intensity of extreme weather events, including heat waves, as IPCC’s 2014 report warns.

“It is difficult to directly link this present single-year high heat-wave occurrence to climate change,” says  Ghosh. “However, there is a good possibility that such heat waves may indicate the adverse impacts of global warming.” A rise in the frequency and intensity of heat waves would increase the risk of heat stroke and heat exhaustion, and even deaths from hot weather, the IIT-B team predicts, echoing concerns raised by IPCC....

Sunset on the Ganges, shot by ptwo, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Food waste costs North America $162 billion

Waste Management World: Food waste in America amounts to $162 billion and between 31% to 40% of American food supply goes to waste, primarily in homes, stores and restaurants, according to a new study. The findings, from the Johns Hopkins Center for a Livable Future (CLF) at the Johns Hopkins Bloomberg School of Public Health, were published in a report in the journal PLOS ONE.

Top food wasted, by weight, include fruit and vegetables yet nearly 75% of Americans believe that they waste less food than the national average, according to the findings.

Furthermore, as a result the food waste places a huge drain on the environment when approximately 30% of the fertiliser, 35% of the fresh water and 31% of the cropland in the US was used to grow food that was eventually wasted.

The first nationally representative consumer survey focused on wasted food sheds some light on factors affecting consumers’ waste. The survey, administered to 1,010 American consumers in April 2014, covered awareness, knowledge, attitudes and behaviors related to wasted food.

Despite the large environmental impacts related to wasted food, most survey respondents listed environmental concerns last when ranking reasons to reduce food waste, with just 10% calling them “very important.” Instead, respondents said that saving money and setting a positive example for children were the top motivators for wanting to throw out less food....

Wasted food, shot by Assianir, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 4.0 International license

Sunday, June 7, 2015

Typhoons a growing threat because of climate change

Peter Hannam in Stuff (New Zealand): A warming planet is already stoking the intensity of tropical cyclones in the north-west Pacific and their ferocity will continue to increase even with moderate climate change over this century, an international research team has found.

A study covering 850 typhoons in the region found the intensity of the damaging storms has increased by about 10 per cent since the 1970s, said Wei Mei, a climate scientist at the Scripps Institution of Oceanography at the University of California, San Diego, and a co-author of the study published in the journal Science Advances.

Using 20 models and a mid-range projection of carbon dioxide emissions, the researchers found the peak intensity of storms such as super Typhoon Haiyan, which tore through the Philippines in November 2013, will become even stronger and more common. Such storms will be 14 per cent stronger by 2100, equivalent to adding another category to the current top severity rating of 5, the study found.

Research on tropical cyclones – known as hurricanes in the Atlantic basin – has sought to identify whether factors contributing to more powerful events such as warmer sea surface temperatures might be countered by changes to ocean or atmospheric circulation that may hinder the storms' genesis or force. Warming in the top 75 metres of the oceans will dominate other influences, the researchers found.

"This projected increase in typhoon intensity is largely due to [sea surface temperatures] warming," the study found, adding that the findings are "at the high end" of previous projections....

Typhoon Haiyan, November 7, 2013

Water security vital to unlocking African prosperity says SAB Miller

Business Day Online: With coordinated action, better water provision in Africa will strengthen economic growth and unlock the path to prosperity for millions, according to SABMiller’s Chief Executive Alan Clark.

Speaking today at the W
orld Economic Forum (WEF) on Africa in Cape Town, Alan Clark highlighted that water security and resource efficiency have become and will remain a priority for SABMiller in Africa as climate change exarcebates competition for resources. This year’s WEF Global Risks Report ranked water scarcity as the biggest single risk to societies and economies.

While growing production volumes, SABMiller has cut its global carbon emissions by 35 percent since 2008, reducing absolute emissions by nearly one million tonnes. Over the same period it cut water use per litre of beer by 28 percent, now using 3.3 litres of water to make one litre of beer, exceeding its 2015 target. In the last year alone, the company reduced its water use by 29 million hectolitres – the equivalent to the water used by over 116,000 Africans each yeari.

This has translated into tangible gains for the company –  SABMiller saved US$117million in the last financial year compared with 2010 through water and energy related initiatives as a key part of its overall cost reduction plans.

Leading a panel discussion on the Future of Water, Alan Clark said: “The business case for conserving water both within our own operations and in the communities where we work is clear and compelling. Companies from all sectors are facing up to the risks that water scarcity poses to their business – even more so with the impact of climate change. Now is the time to step up and make clear commitments to reduce overall water use and improve efficiency.”...

An oasis in Libya, shot by Sfivat