Chimps’ survival hopes jeopardised by climate change

Chimps’ survival hopes jeopardised by climate change

One of our closest animal relatives is at risk of being wiped out as changing rainfall patterns threaten to destroy its Central African habitat.

LONDON, 30 January, 2015 − Climate change is a challenge for chimpanzees, too. New research warns that a primate subspecies – one of humanity’s closest animal relatives – could become endangered within five years

The threatened subspecies of the common chimpanzee is Pan troglodytes ellioti, and there are only 6,000 remaining individuals, surviving in two populations in Cameroon.

Field biologist Paul Sesink Clee, of Drexel University, US, and colleagues report in BMC Evolutionary Biology that they combined climate, environmental and population data to model how the chimpanzees’ preferred habitats would change with climate under a “business as usual” scenario in which the world went on burning fossil fuels.

Habitat change

Underlying such research is the larger question of how variation in habitat drives evolutionary change: why are there four subspecies of chimpanzee, and how much does geography and habitat have to do with it?

So the scientists made a chimpanzee population map, and imposed it on a map of habitats.

They found two distinct populations of the chimpanzee − one in the mountainous rainforests of western Cameroon, and one in a distinctive region of grassland, forest and woodland in central Cameroon.

Then they simulated how these habitats would change under global warming scenarios by 2020, 2050 and 2080.

“Preliminary projections suggest that rainfall patterns will change dramatically in this region of Africa”

Their findings were that the mountain rainforest habitat would survive, but the lowland dwellers would decline quickly under all scenarios by 2020, and could disappear almost entirely under the worst case scenario by 2080.

Since half of the entire population of Nigeria-Cameroon chimpanzees survive in this habitat, the suggestion is that the chimpanzees are particularly vulnerable to climate change.

Severely affected

The researchers did not take into account the opportunities for the chimpanzees to migrate, or to adapt to new circumstances. They point out that Central Africa in particular, and the continent in general, is likely to be severely affected by climate change.

“Preliminary projections suggest that rainfall patterns will change dramatically in this region of Africa, which will result in significant alterations of forest and savanna habitats,” the report says.

“Models of global climate change also have been used to show that 30% of plant and animal species are at risk of extinction if the rise in mean global temperature exceeds 1.5°C − an increase that is nearly certain to occur under future climate scenarios.” – Climate News Network

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California rains bring little relief from harsh drought

California rains bring little relief from harsh drought

Unless substantial rain falls soon, California’s worst drought on record threatens dire consequences for the state’s massive agricultural industry.

DAVIS, CALIFORNIA, 29 January, 2015 − Doing the right thing in the environs of the University of California, Davis – one of the foremost agricultural institutions in the US – means driving a carbon efficient car. And having a lawn that’s burned dry.

California’s worst drought on record is forcing people to cut back radically on water use – and that means letting lawns die. There was considerable rainfall last month, but it was not nearly enough to replenish the badly-depleted water resources.

“If we don’t have rain in significant amounts by early March, we’ll be in dire straits,” says Professor Daniel Sumner, director of the Agricultural Issues Center at Davis.

Water restrictions

Higher than average temperatures – particularly during the winter months – have combined with a lack of rainfall to produce severe drought conditions across much of the state. Water restrictions have been brought in following the imposition of a drought emergency in January last year.

“Historically, California’s water has been stored in the snow pack in the mountains, but warmer winter temperatures have meant the pack has been melting.” Sumner says.

“The agricultural sector has made considerable advances in limiting water use, and new, more drought resistant, crops and plant varieties have been introduced, but aquifers have been pumped and they are not being replenished.

“In the past, massive projects were undertaken to distribute water round the state, but now there’s not the money available to do any more big-time plumbing work. Also, the regulations on diverting water for agriculture use are very tight – rivers can’t be pumped if it means endangering fish stocks or other wildlife.”

“California is still growing – and exporting – rice, which is a real water drinker. How crazy is that?”

Whether or not climate change is causing the drought is a matter of considerable debate. A recent report sponsored by the US government’s National Oceanic and Atmospheric Administration (NOAA) says natural oceanic and atmospheric patterns are the primary drivers behind the drought.

A high pressure ridge that has hovered over the Pacific off California’s coast for the past three years has resulted in higher temperatures and little rainfall falling across the state, the report says.

However, a separate report by climate scientists at Stanford University says the existence of the high pressure ridge, which is preventing rains falling over California, is made much more likely by ever greater accumulations of climate-changing greenhouse gas emissions in the atmosphere.

Whatever the cause of the drought, the lack of rain is doing considerable environmental and economic damage. The Public Policy Institute of California, a not-for-profit thinktank, estimates that $2.2 billion in agricultural revenues and more than 17,000 jobs have been lost as a result of the drought.

Severely depleted

Thousands of acres of woodland have been lost due to wildfires, while fisheries experts are concerned that severely depleted streams and rivers could lead to the disappearance of fish species in the area, such as coho salmon and steelhead trout.

The drought is not limited to California. Adjacent states are also affected, and over the US border to the south, in Mexico’s Chihuahua state, crops have been devastated and 400,000 cattle have died.

Frank Green, a vineyard owner in the hills of Mendocino County, northern California, says: “The vines are pretty robust and, despite the drought, our wines have been some of the best ever over the past two years.

“But there’s no doubt we need a lot more rain, and plenty more could be done on saving and harvesting water. Farmers have cut back on growing water-hungry crops like cotton, but California is still growing – and exporting – rice, which is a real water drinker. How crazy is that?” – Climate News Network

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Increased carbon spill from glaciers sets new puzzle

Increased carbon spill from glaciers sets new puzzle

Samples taken from five continents indicate that a big rise in organic carbon released by melting glaciers could have serious implications for ecosystems.

LONDON, 28 January, 2015 − Researchers in the US have calculated that, thanks to climate change, melting glaciers will have spilled an extra 15 million tonnes of organic carbon into the seas by 2050.

The consequences for the ecosystems that depend on glacial meltwater are uncertain, but this burden of biological soot and sediment has potential implications for the global carbon cycle as well.

The researchers estimate that the dissolved organic carbon released by melting glaciers will be an increase of half as much again on the current flow − the equivalent of about half the annual flow of dissolved carbon down the mighty Amazon River. And their calculations have identified another puzzle for climate scientists trying to understand the carbon cycle.

The planet’s glaciers and ice sheets cover about 11% of the planet’s surface and hold about 70% of the world’s fresh water. Spread thinly through this frozen water is a significant amount of biological carbon, with the Antarctic ice sheet alone hosting 6 billion tonnes of it.

Increased meltwater

It is safe for the time being, but mountain glaciers almost everywhere in the world are in retreat, and meltwater flow from the glaciers that drain the Greenland icecap is on the increase.

Eran Hood, professor of environmental science at the University of Alaska Southeast in Juneau, and colleagues report in Nature Geoscience that they developed a database of dissolved organic carbon found in 300 samples collected from glaciers on five continents.

Some of it was clearly preserved from living things on the ice itself, some of was scraped up as the glaciers moved over old soils, and some of it was soot from fossil fuel combustion or distant forest fires.

There was a wide spread of carbon concentrations in the samples, but it was enough to estimate a global average.

“We know we are losing glaciers, but what does that mean for marine life, fisheries, things downstream
that we care about?”

They also knew that Greenland and Antarctic icebergs delivered 4,250 billion tonnes of water to the oceans each year, and that the run-off from retreating mountain glaciers was somewhere between 369-905 billion tonnes.

So they could begin to make an estimate of the rate at which dissolved organic carbon is re-entering the planetary system, and perhaps augmenting the carbon cycle.

The carbon cycle underwrites all life: plants and microbes withdraw carbon from the atmosphere and some of it gets stored in the soilspreserved as peat, or locked away as rock, or frozen as ice to be returned to the planetary system in all sorts of ways,

New questions

Research like this is basic: it adds another detail or two to an understanding of how the planet works. It starts to answer existing questions − but it also raises new ones.

“This research makes it clear that glaciers represent a substantial reservoir of organic carbon,” said Dr Hood. “As a result, the loss of glacier mass worldwide, along with the corresponding release of carbon, will affect high latitude marine ecosystems, particularly those surrounding the major ice sheets that now receive fairly limited land-to-ocean fluxes of carbon.”

His co-author Robert Spencer, assistant professor of oceanography at Florida State University, said: “The thing people have to think about is what this means for the Earth. We know we are losing glaciers, but what does that mean for marine life, fisheries, things downstream that we care about?” – Climate News Network

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India gives nothing away in climate talks with US

India gives nothing away in climate talks with US

There is no sign from President Obama’s visit that India will be pressured into making any immediate plans to cut its greenhouse gas emissions.

NEW DELHI, 27 January, 2015 − Hopes that India and the US might announce ambitious plans to co-operate in tackling climate change have proved wide of the mark.

A meeting here between the visiting US president, Barack Obama, and Indian prime minister Narendra Modi, showed India determined to follow an independent line − although Modi said it does intend to increase its use of renewable energy.

Mod did not offer any hint of a reduction in coal use. And on possible targets for reducing greenhouse gas (GHG) emissions, he said nothing beyond agreeing to phase out hydrofluorocarbons, while insisting that India demands equal treatment in cutting GHGs.

India is the third largest GHG emitter, after China and the US, but generates only two tonnes of CO2 equivalent per capita, compared with 20 tonnes in the US and eight in China.

Limited liability

The two leaders smoothed the way for further Indian use of nuclear power, outlining a deal to limit the legal liability of US suppliers in the event of a nuclear power plant catastrophe.

Referring to the recent agreement between the US and China to work together on CO2 cuts, Modi said: “The agreement that has been concluded between the US and China does not impose pressure on us; India is an independent country. But climate change and global warning itself is huge pressure.”

Analysts here point out that there has been little time yet for Modi and Obama to develop a strong working relationship, and that it could be premature to dismiss the outcome of this meeting as disappointing.

“The agreement . . . between the US and China
does not impose pressure on us;
India is an independent country.”

Before last month’s UN climate talks in Lima, Peru, India said it had put in place several action plans for achieving Intended Nationally Determined Contributions (INDCs), which are key elements of the bold climate agreement that many governments hope will be signed at the next round of talks in Paris in December.

India continues to maintain that its INDCs will be announced “at an appropriate time with specific contributions”.

Last week, Modi called for a paradigm shift in global attitudes towards climate change – from “carbon credits” towards “green credits”. He urged nations with the greatest solar energy potential to join India in innovation and research to reduce the cost of the technology and make it more accessible.

“Instead of focusing on emissions and cuts alone, the focus should shift to what we have done for clean energy generation, energy conservation and energy efficiency, and what more can be done in these areas,” he said.

Modi and Obama announced action to advance India’s transition to a low-carbon economy, and India reiterated its goal of increasing its solar target to 100 gigawatts by 2022, which the US said it would support.

Ambitious agreement

India’s Ministry of External Affairs said they had “stressed the importance of working together and with other countries to conclude an ambitious climate agreement in Paris in 2015”.

Anu Jogesh, a senior research associate with the Centre for Policy Research’s Climate Initiative, said: “There was a lot of buzz in policy circles and the media that there might be some kind of announcement, not on emission cuts per se but on renewable energy. However, apart from the nuclear agreement, little else has emerged.”

Answering fears that India might become a ready market for US companies, Dr Pradipto Ghosh, Distinguished Fellow at the Energy and Resource Institute, said: “The large scale will inevitably bring down costs and companies will offer competitive prices, and also bring in more reliability, efficiency and product quality.” − Climate News Network

  • Nivedita Khandekar is a Delhi-based independent journalist who writes on environmental, developmental and climate change issues. Email: nivedita_him@rediffmail.com; Twitter: @nivedita_Him

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Climate pushes Doomsday Clock close to midnight

Climate pushes Doomsday Clock close to midnight

Scientists warn that the deadly combination of unchecked climate change and nuclear weapons endangers everyone on Earth unless urgent action is taken.

LONDON, 26 January, 2015 − The two main “extraordinary and undeniable threats to the continued existence of humanity” are more acute than at any time in the last 30 years, according to scientists in the US.

One is the possibility of nuclear war − even a limited one. The other is climate change, which the scientists say “looms over all of humanity”. Either means that “the probability of global catastrophe is very high” without urgent action.

The warning comes from the Bulletin of Atomic Scientists’ science and security board, which has moved the hands of the historic Doomsday Clock forward two minutes. They now stand at three minutes to midnight.

Undeniable threats

The board says in a statement: “In 2015, unchecked climate change, global nuclear weapons modernisations, and outsized nuclear weapons arsenals pose extraordinary and undeniable threats to the continued existence of humanity, and world leaders have failed to act with the speed or on the scale required. . .

“These failures of political leadership endanger every person on Earth.”

The statement says: “The board feels compelled to add, with a sense of great urgency: ‘The probability of global catastrophe is very high, and the actions needed to reduce the risks of disaster must be taken very soon.’”

The Doomsday Clock symbolises how close humanity has come to the apocalyptic danger of mass destruction by nuclear weapons, climate change, and emergent technologies.

The clock’s minute hand stood at two minutes before midnight in 1953, and at 17 minutes before midnight in 1991, after the end of the Cold War. The last time it was just three minutes to midnight was 1983, when “US-Soviet relations were at their iciest”, according to the Bulletin.

“This threat looms over all of humanity. We all need
to respond now, while there is still time.”

Sivan Kartha, a member of the Bulletin’s science and security board and a senior scientist at the Stockholm Environment Institute, said: “Steps seen as bold in light of today’s extremely daunting political opposition to climate action do not even match the expectations of five years ago, to say nothing of the scientific necessity.

“Global greenhouse gas emission rates are now 50% higher than they were in 1990. Emission rates have risen since 2000 by more than in the previous three decades combined. Investments have continued to pour into fossil fuel infrastructure at a rate that exceeds $1 trillion per year, with additional hundreds of billions of dollars in continued fossil fuel subsidies.”

Sharon Squassoni, another board member and director of the Proliferation Prevention Programme at the Center for Strategic and International Studies, said: “Since the end of the Cold War, there has been cautious optimism about the ability of nuclear weapon states to keep the nuclear arms race in check and to walk back slowly from the precipice of nuclear destruction.

“That optimism has essentially evaporated in the face of two trends: sweeping nuclear weapons modernisation programmes and a disarmament machinery that has ground to a halt.

Slowed dramatically

“Although the United States and Russia no longer have the tens of thousands of nuclear weapons they had during the Cold War, the pace of reduction has slowed dramatically in recent years, well before the crisis in Crimea. From 2009 to 2013, the Obama administration cut only 309 warheads from the stockpile.”

Richard Somerville, a board member and research professor at Scripps Institution of Oceanography, University of California, San Diego, said: “Efforts at reducing global emissions of heat-trapping gases have so far been entirely insufficient to prevent unacceptable climate disruption. . .  This threat looms over all of humanity. We all need to respond now, while there is still time.”

The board urges action to be taken to cap greenhouse gas emissions at levels that that would keep average global temperature from rising more than 2°C above pre-industrial levels. This is the internationally-agreed limit, which will form the basis of the global agreement that climate negotiators hope to reach at UN talks in Paris in December.

The board also urges sharply reduced planned spending on nuclear weapons modernisation, a revitalised disarmament process, and immediate action to deal with nuclear waste. − Climate News Network

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Social conscience is key to cutting household energy

Social conscience is key to cutting household energy

Researchers in Los Angeles find that saving money is not the most powerful message in persuading people to reduce the amount of electricity they use.

LONDON, 25 January, 2015 − Altruism is alive and well and living in California. An extended experiment involving more than 100 households suggests that people are more likely to reduce energy use if they believe it is good for the environment rather than good for their pockets.

Those who tuned into the messages about public good saved, on average, 8% on their fuel bills, while households with children reduced their energy use by 19%. But people who were repeatedly reminded that they were using more power than an economy-conscious neighbour altered their consumption hardly at all.

Environmental economist Magali Delmas and research fellow Omar Asensio, of the University of California Los Angeles, report in the Proceedings of the National Academy of Sciences that they were investigating behaviour-altering messages that might encourage energy savings, as Americans could potentially save 20% a year − or 123 million tonnes of carbon.

Real-time use

Smart-metering systems were devised and installed in 118 apartments in a campus village that is home to graduate students and their families.

A website was created so that everybody could track real-time use and see what such things as dish washing machines and heating and cooling systems could cost, and even see the spikes in energy use every time they opened the fridge.

“Electricity is still largely invisible to most people.
We want to help them see it.”

They took six months to measure the baseline use, and then started to send weekly emails to the volunteers.

For four months, one group kept getting messages that said they were using more power than a neighbour, or that their consumption was more costly. The other group was told how much more air pollution they were creating than their neighbour − and, at the same time, reminded that air pollution is linked to childhood asthma, and cancer.

The environmental argument won, conspicuously. And it may have succeeded, the researchers think, because the environmentally-aware households were being presented with two ideas: that if they cut air pollution and reduced the risk of disease they were doing something that would benefit both them and society at large.

Relatively cheap

The pressure to cut household fuel bills may not have worked, said Asensio, because electricity is relatively cheap.

“For most people at our field site, the savings for cutting back to using the same as their most efficient neighbour would only be $4 to $6 a month,” he said. “That’s a fast-food combo meal or a couple of gallons of milk.”

Professor Delmas, the study’s principal investigator, said: “Electricity is still largely invisible to most people. We want to help them see it.” – Climate News Network

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No prospect of relief from constant nuclear headache

No prospect of relief from constant nuclear headache

Keeping nuclear waste safe costs billions of dollars a year, but what to do with it in the long-term is still no nearer being resolved.

LONDON, 24 January, 2015 − A private consortium formed to deal with Europe’s most difficult nuclear waste at a site in Britain’s beautiful Lake District has been sacked by the British government because not sufficient progress has been made in making it safe.

It is the latest setback for an industry that claims nuclear power is the low-carbon answer to climate change, but has not yet found a safe resting place for radioactive rubbish it creates when nuclear fuel and machinery reaches the end of its life.

Dealing with the waste stored at this one site at Sellafield − the largest of a dozen nuclear sites in Britain − already costs the UK taxpayer £2 billion a year, and it is expected to be at least as much as this every year for half a century.

Hundreds of people are employed to prevent the radioactivity leaking or overheating to cause a nuclear disaster, and the cost of dealing with the waste at this site alone has already risen to £70 billion.

Dangerous to humans

This extraordinary legacy of dangerous radioactive waste is present in every country that has adopted nuclear power as a form of electricity production, as well as those with nuclear weapons. No country has yet solved the problem of how to deal with waste that remains dangerous to humans for thousands of years.

Among the many other countries that have a serious unresolved nuclear waste problem are the US, Russia, China, India, Japan, France, Germany and Canada, as well as a number of eastern European countries that have ageing Russian reactors. Only Sweden seems to have practical plans to deal with its nuclear waste, and these are years away from completion.

Many countries, including Germany and Italy, have rejected nuclear power, partly because they cannot find a solution to the waste problem. But many others − including the UK, India and China − intend to go on building them even though it stores up a dangerous radioactive legacy for future generations.

The problem began after the Second World War when, in the rush to build atomic weapons, the governments of the US, Russia and the UK gave no heed to the high dangerous nuclear waste it was creating in the process. This problem continued, even in non-weapon states such as Germany and Japan, when nuclear power was seen as a new, cheap form of electricity production.

Ill-founded hope

The belief was always that science would find some way of neutralising the dangerous radioactivity, and then it could be buried as simply as any other rubbish. This hope has proved to be ill-founded.

Highly radioactive waste, dangerous for as long as 200,000 years, has to be isolated and guarded in every country that has dabbled in nuclear energy. At Sellafield, huge water tanks filled with unknown quantities of radioactive rubbish have yet to be emptied.

The only bright spot is Sweden, which has a deep depository to dispose of short-lived waste in stable granite formations. Other similar depositories are planned along the same lines for more dangerous spent fuel, but these are still at the planning stage.

Long-term problem

Constructing these is likely to take another 30 years, so even in Sweden storing the waste is still a long-term problem. The argument is that once the depositories have been built and sealed, the granite will be stable for millions of years − long enough for the radioactivity to decay to safe levels.

Unfortunately for most countries, they do not have these stable granite formations. Britain has granite in the Lake District, but the rock is fractured and water filters through it, raising the possibility of radioactivity leaching out.

The British government promised four years ago it would not build any more nuclear power stations until it had found a solution to this 50-year-old problem. But it has abandoned the promise because it is no nearer building a Swedish-style depository, even though it is now offering financial bribes to communities to host an underground cavern.

The official position is that Britain is still on course for finding a Swedish-style deep depository for nuclear waste, but no one can say where or when it could be built. – Climate News Network

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Energy poured in to cutting-edge conservation ideas

Energy poured in to cutting-edge conservation ideas

A battery that could treble electric car mileage and cut costs is among the innovations moving closer to reality on the frontiers of science.

LONDON, 23 January, 2015 − Here’s a plan for cutting your carbon footprint: fit your electric car with a high-performance lithium sulphur battery that can treble the mileage for a much lower cost.

That’s just one of many examples of innovative energy conservation solutions that scientists are currently on the brink of turning into reality. Others include fitting your clothes with zinc oxide nano-generators that can harvest mechanical energy from the moving fabric to charge your portable devices.

Then you could move into a new suburban development carefully planned to maintain all the trees that store and sequester carbon. You’ll be in a city anyway − and cities are best placed to plan new energy efficiencies.

Linda Nazar, chemistry professor at the University of Waterloo, Canada, and colleagues believe that a lithium-sulphur battery is one step nearer reality.

Light and cheap

Sulphur is abundant, light and cheap, and a rechargeable sulphur cathode could be so much less costly than the lithium cobalt ion in lithium-ion cells – if only the sulphur could be stopped from dissolving after a few cycles.

She and her team report in report in Nature Communications that ultrathin, nanoscale sheets of manganese oxide could stabilise the sulphides and deliver a cathode that could be recharged more than 2000 times. So far, the Waterloo team claim only to have worked out the mechanism that would stabilise a sulphur battery: there is much more to be done.

Meanwhile, a group at the Korean Advanced Institute of Science and Technology report in Applied Physics Letters that piezoelectric zinc oxide nanotechnology could be used to harvest mechanical energy.

Any movement – any sound, any vibration, any exertion of muscle, any step, any movement of fabric – represents energy that could be turned into electrical current, especially with a little help from exquisitely-designed aluminium nitride insulators.

Illustration showing stacked flexible nanaogenerators (left) Image: Giwan Yoon/KAIST

Illustration showing stacked flexible nanaogenerators (left)
Image: Giwan Yoon/KAIST

So someone wearing, for instance, a medical device that monitors heart rate and breathing could actually provide the power for the device just by walking about, or breathing. That’s the possibility: more exploration is needed, say the scientists.

Both pieces of research are reports from the frontiers of energy conservation science. But at the University of Florida, one group zeroed in on the oldest carbon storage and sequestration technology of all: the tree.

Homes needed

There are 19 million people in Florida now. By 2040, the population could be 25 million. That’s a lot of new homes needed − and it would help if they started off in a conservation-friendly way.

Environmental specialist Richard Vaughn and colleagues report in the journal Landscape and Urban Planning that they looked at a plan to build 1,835 homes on a 700 hectare site that is – for the moment – a managed pine forest.

They grouped the trees according to age and calculated that, since older trees hold more carbon than younger ones, it would make sense to reduce the area for subdivision and group the homes closer together so as to preserve the oldest trees.

One of the designs saved 71% of the original stored carbon and 82% of the carbon that would have been sequestered by the forest.

“If you have a compact subdivision, you’ll have fewer roads,” said one of the Florida report authors, Mark Hostetler, professor specialising in biodiversity conservation. “With fewer roads, you have less energy used to produce the roads.

Patches for wildlife

“That impacts how much carbon is released. With more patches of biodiversity, you also have natural patches for wildlife. And there’s water. With compact neighbourhood design you’ve decreased the pavement and you’ve kind of separated the built areas from the natural areas.”

All urban areas offer scope for energy savings, because all cities generate a higher proportion of carbon emissions than rural areas.

Felix Creutzig. head of the land-use, infrastructures and transport group at Mercator Research Institute on Global Commons and Climate Change, Berlin, and colleagues looked at energy and emissions data from 274 cities in 60 countries – cities home to 21% of the global urban population – and considered the future under a “business-as-usual” scenario.

They report in the Proceedings of the National Academy of Sciences that energy use would triple by 2050. Another two to three billion people would crowd into the cities, and the urban “footprint” would grow by 1.2 million square kilometres – an area the size of South Africa.

Some thoughtful urban planning and energy policies, however, could make a big difference − especially if the planners got to work early.

“This window of opportunity exists especially for low-emissions cities in Asia, the Middle East, and Africa, where urbanisation and associated rises in income could lead to high increases in urban energy use if current trends continue,” they report. – Climate News Network

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Scientists say rise in sea levels is faster than feared

Scientists say rise in sea levels is faster than feared

Harvard researchers find that there has been an almost threefold annual increase in global sea levels over the last quarter of a century.

LONDON, 22 January, 2015 − Sea level rise for most of the 20th century may have been over-estimated by as much as 30%. But the less welcome news is that, if that’s the case, then sea levels since 1990 have started to accelerate more sharply than anyone had ever expected.

Scientists at Harvard University, in the US, report in the journal Nature that they came to the conclusions after deciding that old data needed fresh analysis − using sophisticated mathematical filtering techniques for handling the uncertainties and gaps in such data.

Estimating and accounting for global mean sea level (GMSL) rise is critical to characterising current and future human-induced changes. The catch is that sea level measurement hasn’t been going on for very long, so not all measurement techniques have been the same. In addition, reliable, systematic and sustained sets of data are relatively sparse.

Rise and fall

The term “sea level” sounds pretty basic, but the oceans are hardly ever level. Tides swell and ebb, regions of sea rise and fall according to temperature and salinity, and the shorelines at which researchers take measurements can also go up because of tectonic movement or sink because of the abstraction of groundwater.

Measurements along some of the world’s great estuary systems can be skewed because of human interference over the decades with the flow downstream, and great tracts of ocean cannot be measured directly at all.

The challenge, then, is to arrive at an average sea level rise for the whole planet.

“We know that sea level is changing for a variety of reasons,” said Dr Carling Hay, post-doctoral fellow in Harvard’s Department of Earth and Planetary Sciences (EPS).

“There are ongoing effects due to the last ice age, heating and expansion of the ocean due to global warming, changes in ocean circulation, and present day melting of land-ice − all of which result in unique patterns of sea level change. These processes combine to produce the observed global mean sea level rise.”

So the Harvard scientists, working with colleagues from Rutgers University in New Jersey, made estimates for the meltwater from glaciers and dwindling ice caps, from ocean thermal expansion and factors. They then “smoothed” the data, using a mathematical modelling algorithm.

Earlier estimates put mean sea level rise in the 20th century at between 1.5 and 1.8 millimetres a year. Dr Hay and her colleagues now think that, between 1901 and 1990, the true figure was probably closer to 1.2mm a year.

But since 1990, global sea level has risen by 3mm a year on average. So, in fact, the acceleration since then has been faster than anybody expected – and this in turn could affect future projections.

Question of accuracy

“Another concern with this is that many efforts to project sea level change into the future use estimates of sea level rise over the time period from 1900 to 1990,” said co-author Eric Morrow, a recent Ph.D graduate of Harvard’s EPS

“If we’ve been over-estimating the sea level change during that period, it means that these models are not calibrated appropriately, and that calls into question the accuracy of projections out to the end of the century.”

Dr Hay added: “We expected that we would estimate the individual contributions, and that their sum would get us back to the 1.5 to 1.8mm a year that other people had predicted. But the math doesn’t work out that way.

“Unfortunately, our new lower rate of sea level rise prior to 1990 means that sea level acceleration that resulted in higher rates over the last 20 years is really much larger than anyone thought.” – Climate News Network

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Warming warning as temperatures hit record high

Warming warning as temperatures hit record high

As statistics confirm that 2014 was the hottest year ever recorded, leading scientists say climate change trends are dominated by human emissions of greenhouse gases.

LONDON, 21 January, 2014 − Last year was the warmest year on record, according to two separate analyses by two giant US government organisations.

The findings, which confirm a conclusion that meteorologists confidently predicted last November, mean that 14 of the warmest years on record have happened this century, and nine of the 10 warmest years have been since 2000.

Scientists from the space agency NASA and from the National Oceanic and Atmospheric Administration both examined surface temperature measurements around the planet and decided that 2014 was on average the hottest since 1880 − the earliest year for global records.

Climate cycle

The post-millennial pattern was broken only in 1998 − the year of a super El Niño, when global warming coincided with the peak of a natural climate cycle in the Pacific.

Not surprisingly, 2014 was also recently confirmed as the hottest year ever for the UK, where there have been sustained temperature measurements since 1659.

And World Meteorological Organisation scientists warned last month that 2014 could be a record-breaking year for the continent of Europe as well.

Since 1880, the Earth’s average surface temperature has crept up by 0.8 degrees Celsius, and most of that warming has occurred in the last three decades.

“This is yet another flag to the politicians,
and to all of us”

“This is the latest in a series of warm years, in a series of warm decades,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. “While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases.”

The results are an average: some parts of the US − including the Midwest and the East Coast − were unusually cool, while Alaska, California and Nevada all experienced their highest ever temperatures.

The Goddard Institute analyses were based on measurements from 6,300 weather stations, ship and buoy-based sea surface temperature measurements, and data from Antarctic research stations.

Rowan Sutton, who directs climate research at the National Centre for Atmospheric Science at the University of Reading, UK, said: “By itself, a single year doesn’t tell us too much, but the fact that 14 of the 15 warmest years on record have occurred since the turn of the century shows just how clear global warming has become. This is yet another flag to the politicians, and to all of us.”

Likely to accelerate

And Bob Ward, policy director at the UK’s Grantham Research Institute on Climate Change and the Environment, said the figures exposed the myth that global warming had stopped. The rate of increase in global average surface temperatures had slowed over the last 15 years to about 0.05°C a decade, but was likely to accelerate again.

“Measured over a period since 1951, global mean surface temperature has been rising about 0.12°C per decade,” Ward said. “There is mounting evidence all round the world that the Earth is warming and the climate is changing in response to rising levels of greenhouse gases in the atmosphere.

“Carbon dioxide levels are close to 400 parts per million − 40% higher than they were before the Industrial Revolution, and probably higher than they have been for millions of years.”

No politician, he said, could afford to ignore this overwhelming scientific evidence, or claim that global warming was a hoax. – Climate News Network

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