Yellow submarine is a big hit for Antarctic records

Yellow submarine is a big hit for Antarctic records

A new underwater robot is revolutionising important research into the thickness of the sea ice floating off Antarctica’s coasts by looking up from the depths to create detailed 3-D maps.

LONDON, 27 November, 2014 − For the first time, researchers have begun to collect accurate data on the thickness of the sea ice around Antarctica.

A new underwater robot called SeaBED has begun to deliver a clear picture of the greatest mass of floating frozen water on the planet. And the first evidence is that the ice is thicker than anyone had realised: on average somewhere between 1.4 and 5.5 metres, but sometimes as much as 16 metres or more.

Although scientists can keep an eye on the precise extent of the seasonal ice, thanks to consistent satellite data, looking beneath the rim of floating ice that surrounds the enormous continent has been more of a problem. But it’s a problem SeaBED is now addressing by producing the first detailed, high-resolution 3-D maps of Antarctic sea ice.

Baseline measurement

Ice thickness measurements are not easy. During the Cold War, nuclear submarines routinely cruised under the Arctic Ocean ice, making measurements – for navigational safety reasons, rather than climate research. But, in consequence, when the Arctic ice sheet started to melt and dwindle, researchers had a baseline of accurate measurement.

The Antarctic, however, is a partly-submerged rocky continent that bears a huge burden of snow and ice. Shipboard and shore-based studies can provide only a limited set of measurements of ice thickness off its coasts.

Now Guy Williams, a polar oceanographer at theUniversity of Tasmania Institute for Marine and Antarctic Studies, and colleagues from the British Antarctic Survey  and other institutions, report in Nature Geoscience that at last they have a clearer picture of the ice thickness, and therefore a better chance of calculating how sea ice is likely to change as the planet’s climate continues to warm.

“We can now measure in far greater detail, and were excited to measure ice up to 17 metres thick”

SeaBED, technically described as an autonomous underwater vehicle (AUV), is a little yellow submarine two metres long and weighing 200 kg. It was designed and built by the Woods Hole Oceanographic Institution in the US.

In 2010 and 2012 it made a series of autonomous underwater traverses in lawnmower fashion, at depths of 20-30 metres. Most surveying instruments look down, but this one looks up at the ice above it.

There has been a level of alarm at change in Antarctica in recent years. Although the sea ice during recent polar winters has been greater than ever there has been concern about the rate at which some Antarctic glaciers are melting − with worrying consequences for the rate of sea level rise.

Accurate estimates

So the more accurate the information about the volumes of ice formed and lost, the more accurate the estimates of future sea level rise, and the better the understanding of the polar climate machinery.

The AUV measurements – especially when backed up by direct measurements, radar and satellite studies – promise to provide a real insight into the nature of Antarctic sea ice.

Jeremy Wilkinson, lead investigator at the British Antarctic Survey, says: “We can now measure in far greater detail, and were excited to measure ice up to 17 metres thick.”

David Ferreira, an oceanographer at the University of Reading, who is not one of the authors, called the study “a formidable benchmark” in formulating climate models of the region.

“We strongly depend on the simulation of the sea ice in these models to test possible causes of the Antarctic sea ice expansion,” he said. “Effects of the ozone hole, of melt water from the Antarctic ice sheet, or of sea ice movements are among the plausible candidates, but we are limited by the quality of our models in this poorly-observed region of the world to discriminate between them.” – Climate News Network

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Weather extremes will be the norm as world warms

Weather extremes will be the norm as world warms

The World Bank says the Earth is on an unavoidable path towards a 1.5˚C heat rise by mid-century – but it could reach 4˚C by 2100 unless immediate action is taken to avoid dire impacts for millions of people.

LONDON, 26 November, 2014 − As the planet continues to warm, heat waves and other weather extremes that happen perhaps once in hundreds of years − if ever − would become the “new climate normal”, a World Bank report says.

The consequences for development would be severe: failing harvests, shifting water resources, rising sea-levels, and millions of people’s livelihoods put at risk.

The World Bank report, the third in its Turn Down the Heat series, says even very ambitious mitigation action taken today will not stop global average temperatures reaching about 1.5˚C above their pre-industrial level by the middle of this century. They are already 0.8˚C higher, and likely − on present trends − to reach about 4˚C by 2100.

Poor and vulnerable

“Today’s report confirms what scientists have been saying – past emissions have set an unavoidable course to warming over the next two decades, which will affect the world’s poorest and most vulnerable people the most,” said Jim Yong Kim, President of the World Bank Group.

“We’re already seeing record-breaking temperatures occurring more frequently, rainfall increasing in intensity in some places, and drought-prone regions like the Mediterranean becoming drier. These changes make it more difficult to reduce poverty. . . They also have serious consequences for development budgets.”

“Tackling climate change is a matter of reason,
but also of justice”

The report was prepared for the Bank by the Potsdam Institute for Climate Impact Research (PIK), and the UK independent thinktank, the Overseas Development Institute.

The report’s lead author, Professor Hans Joachim Schellnhuber, director of PIK, said: “Tackling climate change is a matter of reason, but also of justice. Global warming impacts in the next decades are likely to hit those hardest that contributed least to global greenhouse gas emissions: the global poor.”

Chain of impacts

Dr Bill Hare, founder and CEO of the Berlin-based not-for-profit organisation, Climate Analytics, is another lead author of the report. He said: “Assessing the entire chain of climate impacts − for example, how heat waves trigger crop yield declines, and how those trigger health impacts − is key to understanding the risks that climate change poses to development.”

Many of the worst projected impacts can still be avoided by holding warming below 2˚C, the report says. It analyses the probable impacts of 0.8˚C, 2˚C and 4˚C of extra heat on agricultural production, water resources, ecosystem services and coastal vulnerability across Latin America and the Caribbean, the Middle East and North Africa, and parts of Europe and Central Asia.

A common threat across the three regions is the risk posed by heat extremes. State-of-the-art climate modelling shows that “highly unusual” extremes − similar to the heat waves in the US in 2012 and in Russia and Central Asia in 2010 − would increase rapidly under a 4˚C emission pathway. It also shows that the risks of reduced crop yields and production losses increase significantly above 1.5˚C to 2˚C.

Key findings across the regions include:

  • Latin America and the Caribbean: Heat extremes and changing rainfall will damage harvests, water supplies and biodiversity. In Brazil, without further adaptation, crop yields could decrease by 2050 by up to 70% for soya and 50% for wheat with 2˚C of warming. Ocean acidification, sea level rise, cyclones and temperature changes will affect coastal livelihoods, tourism, health, food and water security, particularly in the Caribbean.
  • Middle East and North Africa: A large increase in heat waves, combined with warmer average temperatures, will put intense pressure on already scarce water resources, seriously affecting human consumption and regional food security. In Jordan, Egypt, and Libya, harvests could fall by up to 30% with 1.5˚ to 2˚C warming by 2050. Migration and climate-related pressure on resources may increase the risk of conflict.
  • Western Balkans and Central Asia: Melting glaciers and shifts in the timing of water flows will lead to less water resources in summer months and high risks of torrential floods in Central Asia. In the Balkans, a higher drought risk will affect harvests, urban health and energy generation. In Macedonia, yield losses are projected of up to 50% for maize, wheat, vegetables and grapes at 2˚C warming by 2050.

The report adds that forest damage and thawing permafrost in northern Russia could release carbon and methane. With 2˚C warming by 2050, methane emissions could increase by 20% to 30% across Russia. − Climate News Network

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Rare water data drives heating debate underground

Rare water data drives heating debate underground

Global warming’s effects are being felt even below the Earth’s surface, as researchers find that temperatures are rising not only in oceans, but also in subterranean freshwater sources.

LONDON, 25 November, 2014 − Two great bodies of water have begun to feel the heat. European scientists report that they have evidence that the planet’s groundwater – the subterranean ocean of freshwater that bubbles into wells, freshens desert springs, scours great underground limestone caverns and makes possible the irrigation of crops in the world’s farmlands – may be responding to climate change.

And out on the open sea, average global surface temperatures in the northern summer of 2014 were the highest ever recorded.

Both claims will require verification from other sources: in science, one set of measurements is never enough.

Precious resource

In the case of the groundwater temperature rises, this will not be easy. Although water authorities everywhere are concerned about the depletion of this precious resource, and there are routine chemical and microbiological checks, sustained records of groundwater temperatures are rare.

But a team from ETH Zurich in Switzerland and Karlsruhe Institute of Technology in Germany had an advantage: they had data from four wells near the German cities of Cologne and Karlsruhe, where temperature records have been maintained systematically for nearly 40 years.

They report in the journal Hydrology and Earth System Sciences that, after a detailed study of evidence from the four sources, they were able to identify a pattern of very small but significant rises in the groundwater temperatures that mirrored – but came later than – changes in average temperatures above ground. That is, even far below the surface, global warming is making its presence felt.

Research like this is not easy, and there will be plenty of questions and some argument about how they reached these conclusions.

Warming stages

Groundwater is ancient rainfall that seeped down into the bedrock and filled the pores in the soil. As it is drawn from one source, it moves to fill the gap, so there will be questions about how “old” the water is, how swiftly it is being replenished, how well insulated it is from the surface, and how close it might be to seepage from surface rivers.

However, the data reveals not just a rise in temperatures over the four decades, but also a series of warming stages that echo patterns of warming in the atmosphere far above.

“Global warming is reflected directly in the groundwater, albeit damped and with a certain time lag,” says Peter Bayer, senior scientist in engineering geology at ETH Zurich.

Meanwhile, Axel Timmermann, professor of oceanography at the University of Hawaii’s International Pacific Research Centre, says that global mean sea surface temperatures in 2014 were the highest ever recorded.

They were higher even than those of 1988, a year marked by a powerful El Niño event that warmed the Pacific and reversed climate patterns, with sometimes catastrophic consequences in the form of floods, droughts, windstorms, forest fires and harvest failures.

Unexpected slowdown

The 2014 ocean warming may have brought to an end the so-called global warming hiatus, in which average surface air temperatures rose only very slowly between 2000 and 2013.

While there have been a number of possible explanations for this unexpected slowdown – unexpected because greenhouse emissions have increased in that time – there has been no clinching argument. But Timmerman says that the long pause may have come to an end.

He says: “The 2014 global ocean warming is mostly due to the North Pacific, which has warmed far beyond any recorded value and has shifted hurricane tracks, weakened trade winds and produced coral bleaching in the Hawaiian islands.

“Record-breaking greenhouse gas concentrations and anomalously weak North Pacific summer trade winds, which usually cool the ocean surface, have contributed further to the rise in sea surface temperatures. The warm temperatures now extend in a wide swath from just north of Papua New Guinea to the Gulf of Alaska.” – Climate News Network

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Iron’s mixed blessing for health of oceans

Iron’s mixed blessing for health of oceans

New research shows that iron fertilisation stimulates growth of the plankton that help transport carbon dioxide to the deep ocean – but swells the number of small creatures who feed on plankton and whose shells put CO2 back into the atmosphere.

LONDON, 16 November, 2014 − Technology’s answer to climate change in a world in which humans go on releasing carbon dioxide in the atmosphere has just had another setback. The idea of fertilising the planet’s oceans with iron filings to stimulate green growth and turn the oceans into a carbon sink isn’t so simple as hoped.

Two studies – both involving experiments at sea – have confirmed that trace elements such as iron affect plankton growth, and that more iron can mean more carbon dioxide exported to the sea bed in the form of dead and buried life forms. But new research in Nature Geoscience shows that the story is more complex.

Ian Salter, bioscience researcher at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Germany, and colleagues report that they took a closer look at what happens around the Crozet Islands in the Southern Ocean − basaltic islands that deliver a steady natural supply of iron to the surrounding waters.

Carbon pumped

More iron meant more phytoplankton, which meant that more carbon was pumped into deeper waters. But more phytoplankton also meant more little creatures such as foraminifera, which graze on phytoplankton, and then make shells of calcium carbonate − a process that puts carbon dioxide back into the atmosphere.

Dr Salter and his colleagues estimate that the carbonate manufacture in waters naturally fertilised by iron reduced the overall amount of carbon transferred to the deep ocean by between 6% and 32%, whereas in waters not fertilised by iron, the reduction was 1% to 4%. So added iron might make the phytoplankton grow, but it also soups up the return of carbon dioxide to the atmosphere.

The finding is not conclusive. It doesn’t settle the question of whether the presence of trace iron ultimately assists the removal of more carbon from the atmosphere in the long term.

It also doesn’t answer questions about how things might work in warmer waters, and doesn’t offer a guide to the overall effect of iron deliberately added to waters where the phytoplankton don’t bloom in profusion.

“We are in the middle of an experiment we cannot reverse, but which we still don’t understand . . .”

But it does provide a snapshot of science in action, and is yet another reminder that the climate system – and especially the traffic in carbon between rock, water, air and living tissue – is immensely complex, and still puzzling.

And if that wasn’t already clear, new research in the Proceedings of the National Academy of Sciences confirms that there is a lot more to be learned about the role of oceans in climate science.

Researchers report that ocean temperatures have been far more variable over the last 7,000 years than anyone had realised.

Thomas Laepple, a climate scientist at the Alfred Wegener Institute, and Peter Huybers, Professor of Earth and Planetary Sciences at Harvard University, US, combed the climate archives, examined indirect evidence from sediment cores and corals and other sources, and reconstructed sea surface temperatures in a range of different locations over a period of thousands of years.

Then they picked 20 climate models and conducted more than 100 test runs to see if they could simulate the same pronounced fluctuations in ocean temperatures in the same places over the same timescale

Greater discrepancies

They could − but only for short periods. The longer the time sequence, the greater the discrepancies. Over timescales of a thousand years, the models underestimated the variations by a factor of 50.

“Fundamentally, there are only two explanations,” Dr Laepple says. “Either the climate archives do not provide reliable temperature data, or the climate models underestimate the variability of the climate. Or both may be true to some extent.”

Neither finding suggests that climate scientists don’t know what they are doing. In fact, quite the reverse: researchers are establishing just what they can be sure about, and what remains uncertain.

Nor does either finding suggest that long-term alarm over the consequences of increasing levels of atmospheric carbon dioxide is based on uncertain science.

Dr Laepple says: “We are in the middle of an experiment we cannot reverse, but which we still don’t understand well enough to make clear statements at the regional level on longer timescales. Unfortunately, we will just have to continue with this uncertainty for some time.” – Climate News Network

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Lugworm’s turn to feel effects of ocean acidity

Lugworm’s turn to feel effects of ocean acidity

Researchers in the UK have found evidence that a marine worm is being damaged by the increasing ocean acidification that was widely thought to imperil mainly shellfish and coral.

LONDON, 27 October, 2014 − A common marine worm has alerted scientists to the likelihood that the effects of ocean acidification may be more widespread and severe than they had realised.

The lugworm (Arenicola marina) − common on the coasts of Europe and North America, where it can grow to 30 cms in length and is a bait popular with anglers − is being affected by rising levels of acid in the coastal seas. The acid is reported also to be affecting sea urchins.

This is further confirmation that ocean acidification is affecting species other than those that scientists call calcifying organisms − creatures that rely on calcium carbonate to form shells and similar structures.

The pH (a measure of acidity – the lower the pH, the more acidic the water) of the planet’s oceans is dropping rapidly, largely because the carbon dioxide levels in the atmosphere are increasing. Since carbon dioxide dissolves in water to form carbonic acid, the seas are responding to global change.

Highest rate

Scientists say the oceans are now 30% more acidic than they were at the beginning of the industrial revolution about 250 years ago. The current rate of acidification is thought to be the highest for 65 million years.

Among the sea species most vulnerable to acidification are shellfish, coral and other creatures − including some species of plankton − which suffer because the build-up of acid prevents them from developing their calcium shells. Animals further up the marine food chain are also at risk when their prey feels the acidity’s effects.

Researchers at the University of Exeter’s College of Life and Environmental Sciences in the UK have now found that other creatures are also being affected because the growing acidity is increasing their vulnerability to coastal pollutants such as copper.

Writing in the journal Environmental Science and Technology, they explain how they found that the extra copper harms lugworms’ sperm, meaning that their young fail to develop properly. They say: “Larval survival was reduced by 24% when exposed to both OA [ocean acidification] and copper combined, compared to single OA or copper exposures.”

Toxic effects

Sperm motility − the ability of the sperm to swim strongly − was damaged by both OA and copper alone, but with added toxic effects when both factors were combined. Individually, both OA and copper also reduced the lugworms’ fertilisation success.

One of the report’s authors, Dr Ceri Lewis, a marine biologist at Exeter, told BBC News: “It’s a bit of a shock, frankly. It means the effects of ocean acidification may be even more serious than we previously thought. We need to look with new eyes at things that we thought were not vulnerable.

“Our work means we are underestimating effects of acidification for coastal invertebrates. We are now realising there are many indirect impacts of ocean acidification on other processes. It could be that we are facing a lot more surprises ahead.”

Dr Lewis told the Climate News Network: “Lugworms do as important a job as gardeners of our beaches as earthworms do on land, and they bring oxygen down to the underwater sediments. The discovery that they too are affected means there’s a whole new area of concern now, looking at the indirect effect of pollutants and at other species that may be harmed as the acidification increases.”

She has also found more evidence that copper pollution is damaging another marine species − sea urchins. They are already affected by the seawater’s increasing acidity, which means they have to spend more energy on making their shells and spines. − 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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Oceans’ greater heat explains warming ‘pause’

Oceans' greater heat explains warming 'pause'

New technology is helping scientists to re-assess how much heat is being absorbed by the world’s oceans – much more in some regions than realised, they say.

LONDON, 7 October 2014 – One of the most hotly-argued questions in climate research – whether global warming has slowed or even stopped – appears to have been definitively answered. And the scientists’ conclusion is unambiguous: the Earth continues to warm at a dangerous pace.

All that’s happening, they say, is that the extra heat being produced – mainly by the burning of fossil fuels – is concentrating not in the skies but in the seas. They have found new evidence that backs them up.

Instead of driving up the temperature of the atmosphere quite as fast as predicted, the evidence shows that the heat from greenhouse gas emissions is warming the oceans much more rapidly than had been realised.

In some regions the water appears to have been warming, for over 40 years, more than twice as quickly as thought, for instance in the upper 2,300 feet (700 metres) of the southern hemisphere’s oceans.

Paul Durack from the Lawrence Livermore National Laboratory in California and colleagues compared direct and inferred sea temperature measurements with the results of climate models. Together the three sets of measurements suggest estimates of northern hemisphere ocean warming are about right.

Serious under-estimate

But the team report in Nature Climate Change their estimate that warming in the southern seas since 1970 could be far higher than scientists have been able to deduce from the limited direct measurements from this under-researched region. Globally, they conclude the oceans are absorbing between 24 and 58% more energy than thought.

The researchers were able to use data from satellites and from a new source – Argo floats, a fleet of more than 3,000 free-floating monitors which drift through the water and measure the temperature and salinity of the upper 6,500 feet (2,000 m) of the ocean.

A year ago, the Intergovernmental Panel on Climate Change published its Fifth Assessment Report. Professor Chris Rapley, a former director of both the British Antarctic Survey and  the Science Museum in London, told the Climate News Network then of his alarm at what the IPCC said about the oceans.

He said the Earth’s energy imbalance, and evidence that the 93% of the energy build-up absorbed by the oceans continued to accumulate, meant the slow-down in the rise of surface temperatures appeared “a minor and temporary fluctuation”.

Speaking of the latest research, Profesor Rapley told the Network: “The newly reported results of a combination of satellite altimetry measurements of globally mapped sea level rise combined with ocean heat modelling, and a further analysis of the in situ measurements from the Argo buoys, add to the evidence that the so-called ‘pause’ in global warming is confined to surface temperature data, whilst the planet’s energy imbalance continues unabated.

Cold depths

“Once more we need to assess our appetite for risk, and consider seriously what measures we should take to minimise the threats to food and water supplies, the impacts of extreme weather, and the consequences of these to the world economic system and human wellbeing.”

A second study, also published in Nature Climate Change, by scientists at NASA’s Jet Propulsion Laboratory in Pasadena, California, concluded tentatively that all ocean warming from 2005 to 2013 had occurred above depths of 6,500 feet, and that it was not possible to detect any contribution by the deep oceans to sea level rise or energy absorption.

Josh Willis, a co-author of this study (which like that by Dr Durack and his colleagues results from the work of NASA’s newly-formed Sea Level Change Team)  said the findings did not throw suspicion on climate change itself. He said: “The sea level is still rising. We’re just trying to understand the nitty-gritty details.”

This study therefore leaves several questions still unanswered. Will more research find evidence that deep water is in fact warming, for instance? Why are the oceans now apparently absorbing more heat than they once did? And if the southern oceans are heating up faster, then may that help to speed up Antarctic ice melt?

One urgent question that needs answering is how much longer the water near the surface can continue to absorb the extra heat which human activities are producing. Another is what will happen when the oceans no longer absorb heat but start to release it. The answers could be disturbing. – Climate News Network

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Surfers fear climate will wipe out big waves

Surfers fear climate will wipe out big waves

Dedicated surfers, deeply involved with monitoring the natural coastal environment around the world, warn that climate change now poses a major threat to this booming leisure industry.

LONDON, 5 October, 2014 − The world’s oceans are alive with surfers enjoying one of the fastest growing leisure activities. It is estimated there are now at least 35 million people around the globe who regularly ride the waves, and many thousands of people are employed in what has grown into a multi-billion dollar industry.

A warming world should be good news for all those artists of the waves. Warming oceans mean more storms, and the theory goes that more storms will lead to ever bigger waves. So why then are surfing websites – the internet is waterlogged with them – full of concern about changes in the climate?

Two studies appearing in the journal Nature Climate Change have made surfers stand up on their boards and reconsider the situation.

A study led by Dr Andrew Dowdy, a researcher at the Centre for Australian Weather and Climate Research (CAWCR) predicts that rising temperatures will in fact reduce the number of storms causing big waves by the end of the century on the central east coast of Australia.

Potentially destructive

The storms that do occur could be more intense and potentially destructive – but the consistency of wave patterns will be reduced.

That’s bad news for surfers of the future in that area – one of the world’s surfing hotspots. They’ll just have to move elsewhere. Dowdy told the Climate News Network that his projections only relate to that particular region, and they are not necessarily applicable to other coastal regions.

But another study, led by Mark Hemer, a senior research scientist at CAWCR, indicates that surfers might be having to ride smaller waves in future in other parts of the world as well.

Using ocean modelling techniques, Hemer and his colleagues predict a decrease in annual wave height over more than 25% of the global ocean area by the end of the century. The North Atlantic is likely to see a decrease in wave heights during all seasons, and waves are likely to be smaller in the winter months in the North Pacific and Indian Ocean.

But all is not lost. The study predicts that some regions − including  the waters off the south coast of Australia and New Zealand − will see bigger waves of between 5% and 10% above present size averages during winter months.

Surfers are worried about other climate change related threats to their activities. There are fears that rising sea levels could threaten key surfing areas.

Surfers regularly monitor water conditions – everything from acidity levels to rubbish content and sewage levels in the seas.

Surf zone

The Save the Waves Coalition − a US-based group that lobbies to protect the coastal environment, with a particular focus on what it calls the surf zone − monitors development activities in surfing areas worldwide.

Its “endangered waves” campaign lists projects that threaten key surfing areas – from plans to construct a nuclear power station on the coast of South Africa to a series of coal-fired power plants proposed for the coast of Chile.

And Climate change is seen as a major challenge facing the surfing industry.

“The unfortunate truth is that the threats to surfing habitat are now growing exponentially due to the impacts of man-made climate change,” says the California-based Sustainable Surf organisation. – Climate News Network

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Hungry invader fish stripping Mediterranean bare

Hungry invader fish stripping Mediterranean bare

Warming seas are extending the range of tropical rabbitfish, whose voracious appetite for seaweed and other marine vegetation is turning areas of the Mediterranean Sea into rocky barrens.

LONDON, 3 October, 2014 − Scientists in Australia, Europe and the US have identified a new menace in the Mediterranean. The tropical rabbitfish has arrived in the eastern Mediterranean Sea and − wherever the waters are warm enough −  threatens to do to the marine vegetation what the terrestrial rabbit did to Australia’s tender grasses: eat the lot.

A team of researchers led by Adriana Vergés, a marine ecologist at the University of New South Wales in Sydney, Australia, and Fiona Tomas, assistant professor at the Mediterranean Institute for Advanced Studies in Mallorca, Spain, report in the Journal of Ecology that they surveyed 1,000 kilometres of coastline around Turkey and Greece.

Dominant species

They found that two species of rabbitfish have become dominant in the region, and they think the invader is likely to claim more territory as the world’s climate changes and the waters warm.

The range expansion of the rabbitfish, which first entered the Mediterranean basin from the Red Sea via the Suez Canal, provides a good example of how tropical herbivorous fish can impact on the structure of rocky bottoms in temperate seas.

“The study identified two clearly distinct areas −  warmer regions with abundant rabbitfish, and colder regions where they are rare or absent,” Dr Vergés said.

”The regions with abundant rabbitfish had become rocky barrens. There was a 65% reduction in large seaweeds, a 60% reduction in other algae and invertebrates, and a 40% reduction in the overall number of species present.”

The hungry herbivores were first reported in the eastern Mediterranean in 1927, and have recently been found off the coast of Croatia and even the south of France.

The invaders are a threat to ecosystems because seaweed forests − like terrestrial forests − provide food and shelter for hundreds of species.

Feeding behaviour

The researchers recorded fish feeding behaviour and noted that the rabbitfish were not noticeably more greedy than the natives. But whereas the native temperate herbivores grazed only on adult algae, the two species of rabbitfish consumed both the adult and the juvenile seaweeds. The consequence is that the full-grown species were not replaced.

In the long run, such seaweed clearance could be a threat not just to Mediterranean ecosystems but also to the Mediterranean diet, because these ecosystems ultimately support the shoals of sardines, anchovies, red mullet, sea bass, bream, tuna and other specialties of the tables of Spain, Greece and Italy.

“This research highlights the need to work out how the interactions between different species will change in a warming world,” Dr Vergés said. − Climate News Network

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Ice melt dilutes Arctic sea’s CO2 clean-up role

Ice melt dilutes Arctic sea’s CO2 clean-up role

New scientific research confirms that global warming is melting increasingly larger areas of Arctic sea ice − and reducing its vital function of removing CO2 from the atmosphere.

LONDON, 26 September, 2014 − The Arctic ice cap has just passed its summer minimum – and it’s the sixth lowest measure of sea ice recorded since 1978, according to scientists at the US space agency NASA.

For three decades, the shrinking Arctic ice – and the growing area of clear blue water exposed each summer – has been a cause of increasing alarm to climate scientists.

Polar seasonal changes are measured annually by NASA, but reliable satellite data goes back only to 1978, For much of the 20th century, the Arctic was part of the Cold War zone, so only Soviet naval icebreakers and US nuclear submarines took consistent measurements − and neither side published the data.

But studies of 17th and 18th century whaling ships’ logbooks and other records make it clear that the ice once stretched much further south each summer than it does today.

Steady decline

In the last 30 years, the thickness and the area of the ice have both been in steady decline, with predictions that in a few decades the Arctic Ocean could be virtually ice free by September, opening up new sea routes between Asia and Europe.

This year could have been worse, although the area of ice fell to little more than 5 million square kilometres − significantly below the 1981-2010 average of 6.22 million sq km.

“The summer started off relatively cool, and lacked the big storms or persistent winds that can break up ice and increase melting,” said Walter Meier, a research scientists at NASA’s Goddard Space Flight Centre. “Even with a relatively cool year, the ice is so much thinner than it used to be. It is more susceptible to melting.”

Warming in the Arctic is likely to affect climate patterns in the temperate zones, and the state of the polar ice has become of such concern that researchers are using ground-based and sea-based monitors to explore the physics of the phenomenon.

But there is another reason for the attention: as polar ice diminishes, so does the planet’s albedo − its ability to reflect sunlight back into space.

So, as the ice shrinks, the seas warm, making it more difficult for new ice to form. And greater exposure to sunlight increases the probability that permafrost will thaw, releasing even more greenhouse gases locked in the frozen soils.

Now researchers have found another and unexpected example of climate feedback that could affect the cycle of warming. Climate scientist Dorte Haubjerg Søgaard, of the Greenland Institute of Natural Resources and the University of Southern Denmark, and research colleagues have discovered that sea ice itself is an agency that removes carbon dioxide from the atmosphere.

That the oceans absorb the stuff, and tuck it away as calcium carbonate or other marine minerals, is old news.

“But we also thought that this did not apply to ocean areas covered by ice, because the ice was considered impenetrable,” Søgaard said. “However, new research shows that sea ice in the Arctic draws large amounts of CO2 from the atmosphere into the ocean.”

The research is published in four journals, Polar Biology, The Cryosphere, The Journal of Geophysical Research: Atmospheres and Marine Ecology Progress Series.

Two-stage pattern

The Danish research team observed a complex, two-stage pattern of gas exchange as ice floes formed off southern Greenland. They measured the role of atmospheric carbon dioxide in the formation and release of calcium carbonate crystals form in the sea ice, and kept a tally during a 71-day cycle of the carbon dioxide budget.

In the course of this complicated bit of natural cryo-chemistry, they found that some CO2 was carried deep into the ocean with dense, heavy brines, as the ice froze and some was captured by algae in the thawing ice.

They also identified a third factor: the “frost flowers” that formed on the new ice had an unexpectedly high concentration of calcium carbonate.

The profit-and-loss accounting meant that every square metre of ice effectively removed 56 milligrams of carbon from the atmosphere during the 71-day cycle. Over an area of 5 million sq km, this would represent a significant uptake.

But the real importance of the discovery is that scientists have identified yet another way in which the ice – while it is there – helps keep the Arctic cold, and yet another way in which carbon dioxide is absorbed by the oceans.

“If our results are representative, then the sea ice plays a greater role than expected, and we should take account of this in future global CO2 budgets,” Søgaard said. – Climate News Network

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