‘Hidden’ warming points to more record temperatures

‘Hidden’ warming points to more record temperatures

As scientists seek to explain the apparent slowing in global warming this century, the future seems clear: without a huge cut in emissions, there’s hotter times ahead.

LONDON, 28 July, 2015 − Global warming has seemingly slowed because the top 100 metres of the Pacific Ocean has cooled −  or it could be because natural climate cycles keep the atmosphere relatively cool for three decades and then warming accelerates for the next 30 years or so.

But while climate scientists are still trying to understand precisely why the rate of global warming this century has apparently slowed, they predict that the record-breaking temperatures in 2014 will be surpassed this year.

Potential explanations for this so-called pause are like London buses: you wait for a while, and then two come along at once.

Researchers from the US report in the journal Science that the planet has absorbed more heat than it has radiated back into space, but the extra warming is trapped, for the moment, somewhere between the 100 metre and 300 metre layers of the Pacific and Indian Oceans. That is, the warming is there, but you just can’t feel it yet.

Robust evidence

“In the long term, there is robust evidence of unabated global warming,” says Veronica Nieves, a research physicist at the NASA Jet Propulsion Laboratory in California.

Meanwhile, an essay in The Geoscientist argues that natural decadal climate cycles and the continuous rise in greenhouse gases from human combustion of fossil fuels are interacting in ways that mean that the rate of change is not a smooth upward curve, but a series of steps − some steep, some flat.

Average global temperatures have risen 0.9°C since the start of the 20th century. But research scientist Andy Chadwick, of the British Geological Survey, writes: “Anthropogenic emissions are not the only game in town, and that is why the observed temperature variation is more complex.”

Neither argument excludes the other. Both could be true, and each could be only part of the explanation. So could some of the other published analyses.

Scientists have recently argued that the missing heat may be deep in the Atlantic, or driven to depths by the Pacific trade winds,  or affected by natural cycles in both oceans.

“It is clear that, in coming decades, temperatures will continue to rise − albeit not at a uniform rate”

One group has reasoned that a recent burst of low-level volcanic activity could be screening the sunlight and lowering temperatures, while others say they never expected global warming to be consistent.

Yet others have proposed that warming continues and that the anomalies may lie in the way the data has been collected, or that even if the average temperature rises seem to have slowed, the increase in extremes of heat around the world suggests otherwise.

Computer simulation

But much of such argument has been supported by computer simulation and “what-if” logic.

Dr Nieves and her colleagues looked at direct ocean temperature measurements collected over the last 20 years − some of them from a network of 3,500 floats known as the Argo array − to build up a picture of heat driven below the ocean surface, piling up in the Western Pacific, and even “leaking” into the Indian Ocean.

This is while the water surfaces remained unexpectedly cool, during a 30-year phase known to oceanographers and climate scientists as the Pacific Decadal Oscillation.

Dr Chadwick went back to records dating from the close of the 19th century to show a clear warming of more than 100 years, but divided into 30-year “ramps” when temperatures rose steeply, and “steps” when temperatures were roughly constant or fell very slightly, in ways consistent with natural oscillations in ocean and atmosphere.

Temperatures fell between 1880 and 1910, and between 1945 and 1975, and had “flattened off” in the 21st century. The long-term trend correlated closely with the rise in carbon dioxide levels in the atmosphere. And simulations of the future suggested more rapid warming to come.

“It is clear that, in coming decades, temperatures will continue to rise,” Dr Chadwick predicts, “albeit not at a uniform rate.” – Climate News Network

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Global warming’s record-breaking trend continues

Global warming’s record-breaking trend continues

Detailed update by hundreds of scientists on climate indicators in 2014 reveals highest recorded rises in temperatures, sea levels and greenhouse gases.

LONDON, 22 July, 2015 – Forget talk of a slowdown in global warming. Scientists say the climate is heading smartly in the opposite direction, with 2014 proving to be a record-breaking year.

The US National Oceanic and Atmospheric Administration (NOAA), one of the most respected sources of climate science, says that last year “the most essential indicators of Earth’s changing climate continued to reflect trends of a warming planet”. Some − including rising land and ocean temperatures, sea levels and greenhouse gases − reached record highs.

The authoritative report by the NOAA’s Centre for Weather and Climate at the National Centres for Environmental Information (NCEI), published by the American Meterological Society, draws on contributions from 413 scientists in 58 countries to provide a detailed update on global climate indicators.

“The variety of indicators shows us how our climate is changing, not just in temperature but from the depths of the oceans to the outer atmosphere,” says Thomas R. Karl, director of the NCEI.

Rising concentrations

The authors report that concentrations of greenhouse gases continued to climb during the year. Atmospheric carbon dioxide concentrations rose by 1.9 parts per million (ppm), reaching a global average of 397.2 ppm for the year. This compares with a global average of 354ppm in 1990 when the first edition of this report was published. And levels of methane and nitrous oxide also went up.

“Variety of indicators shows how our climate is changing, not just in temperature but from the depths of the oceans to the outer atmosphere”

Four independent global datasets showed that 2014 was the warmest year on record, with the warmth widespread across land areas.

Europe experienced its warmest year; Africa had above-average temperatures across most of the continent throughout 2014; Australia recorded its third warmest year; and Mexico had its warmest. Eastern North America was the only major region to experience below-average annual temperatures.

Global average sea level rose to a record high, and the globally averaged sea surface temperature was also the highest recorded. The warmth was particularly notable in the North Pacific Ocean, where temperatures are in part probably driven by a transition of the Pacific decadal oscillation – a recurring pattern of ocean-atmosphere climate variability centred in the region.

Earlier snow melt

The Arctic continued to warm, and sea ice extent remained low. Arctic snow melt occurred 20–30 days earlier than the 1998–2010 average. On the North Slope of Alaska, record high temperatures at a 20-metre depth were measured at four of five permafrost observatories. The eight lowest minimum sea ice extents during this period have occurred in the last eight years.

But temperature patterns across the Antarctic showed strong seasonal and regional patterns of warmer-than-normal and cooler-than-normal conditions, resulting in near-average conditions for the year for the continent as a whole. Last year was the third consecutive year of record maximum sea ice extent in the Antarctic.

The El Niño-Southern Oscillation (ENSO), a periodic warming of the water in the central and eastern Pacific that disrupts weather over thousands of miles, was in a neutral state during 2014, although it was on the cool side of neutral at the beginning of the year and approached warm El Niño conditions by the end of the year. This pattern played a major role in several regional climate outcomes.

There were 91 tropical cyclones in 2014, well above the 1981-2010 average of 82 storms. But the North Atlantic season, as in 2013, was quieter than most years of the last two decades with respect to the number of storms. – Climate News Network

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Loss of seabirds highlights double danger for species

Loss of seabirds highlights double danger for species

Scientists say increasing human impacts on habitat are combining with climate change to put serious survival stresses on species and ecosystems.

LONDON, 17 July, 2015 − A grim decline of seabird populations, native trout being driven out because of the warming of Canadian lakes, and the destruction of an entire ecosystem in the US are all highlighted in new research.

The combined evidence shows that climate change offers a part-explanation for all three observations − but human pressure and human destruction of habitat are mostly to blame.

The world’s seabirds – such as terns, albatrosses, cormorants, gulls and petrels – are quietly flying away to nowhere.

In the lakes of Ontario, the warm water-loving bass is beginning to drive out the native trout.

And in the Great Basin of the United States, a whole ecosystem has become impoverished as the flow of energy through the vegetation and its animal populations has dwindled.

Biologists’ warning

Marine biologists have for decades been warning about the state of the world’s oceans, and seabird populations are one measure of ocean health.

Michelle Paleczny, a researcher at the University of British Columbia Fisheries Centre in Vancouver, and colleagues report in the Public Library of Science journal PLOS One that they compiled a global database of seabird population records and then examined the population trends in colonies monitored between 1950 and 2010.

This monitored population added up to about 19% of the global count of seabirds and showed a grim decline. Overall, seabird counts had fallen by more than 69% − which adds up to 230 million birds − in the past six decades, and those seabirds that ranged the widest seemed to fare the worst.

In some cases, global warming as a consequence of the build-up of carbon dioxide levels in the atmosphere because of fossil fuel burning has altered the water chemistry and local climate and food supplies for seabird colonies.

But the greatest damage followed other human activity: devastation by fishing fleets, plastic and oil pollution, the introduction of new predators, and entanglement in fishing gear all took their toll. Albatross species in particular are killed in huge numbers each year as they become snagged in fishing fleet long lines.

“Our work demonstrates the strong need for increased seabird conservation effort internationally,” Paleczny says. “Loss of seabirds causes a variety of impacts in coastal and marine ecosystems.”

“We are just beginning to understand
the variety of indirect consequences
related to climate change”

Sport fishing in Ontario contributes an estimated $2bn to the local economy, but fisheries officers and scientists may not be able to conserve the brook trout the anglers cast for.

That’s because the fresh waters are warming, and bass − which prefer warm water − are migrating north to out-compete the local population.

Karen Alofs, a researcher in the Department of Ecology and Evolutionary Biology at the University of Toronto, and others looked at data for 30 fish species from 1,500 lakes – the province has 250,000 lakes altogether – to map the northward advance of the bass in the last 30 years.

Such research, published in the Proceedings of the Royal Society B, is intended to help conservators by offering a guide to how local ecosystems could change.

“It’s important to anticipate how climate change will shape future fish communities, and ultimately fishing opportunities and the sustainability of aquatic ecosystems,” Alofs says. “We are just beginning to understand the variety of indirect consequences related to climate change.”

Vast watershed

But although change in that vast watershed of western US and Mexico called the Great Basin is contemporaneous with the Industrial Revolution, and the rise of carbon dioxide levels in the atmosphere, other human activities may have triggered the dramatic alteration.

Rebecca Terry, assistant professor in the Department of Integrative Ecology at Oregon State University, and a colleague report in the Proceedings of the National Academy of Sciences that they used fossilised owl pellets preserved in a cave to measure changes in the ecosystem over a 13,000 year span.

The pellets are regurgitated by owls after they feed, and contain fragments of bone and other tissue from small mammals caught through the millennia. So each stony little segment of dried vomit is a database of local conditions at the time of digestion and regurgitation.

The message of the ancient bones, teeth and hair is that the basin was once a huge reservoir of living, flowing energy. At the end of the Ice Age, forests and sagebrush steppe gave way to desert shrubland, but the flow of energy – from sunlight to foliage to herbivore and carnivore – remained more or less constant.

And then an invasive grass that arrived with western settlers began to change the picture; mammal size dwindled, and the region became ecologically poorer.

“They show a dramatic breakdown in ecosystem behaviour since the late 1800s, in a way that doesn’t parallel what happened when major climatic warming took place at the end of the last Ice Age,” Dr Terry says.

“The current state is driven by human impacts to habitat, and these impacts have been a stronger force in shaping the mammal community over the last century than just climate change.” – Climate News Network

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Climate change may knock seafood off the menu

Climate change may knock seafood off the menu

Researchers warn of a serious threat to fish, mussels and other marine species as carbon dioxide acidifies the world’s waters and increases temperatures.

LONDON, 7 July, 2015 – Pink salmon – the smallest and most abundant of the Pacific salmon species, and a supper table mainstay in many parts of the world – may be swimming towards trouble.

And they are not the only dish likely to disappear from the menu. Mussels, oysters, clam and scallop could all become scarcer and more expensive as the seas become more acid. And as the world’s waters warm, fish will start to migrate away from their normal grounds at an ever-increasing rate.

New research shows that as the world’s waters acidify because of carbon dioxide levels in the atmosphere, the pink salmon (Oncorhynchus gorbuscha) could become smaller and less likely to survive.

Potentially problematic

Previous studies have repeatedly and consistently explored potentially problematic consequences of change in the pH value of the world’s oceans. The higher the carbon dioxide concentrations in the air as a consequence of the burning of fossil fuels, the greater the change in oceanic acidity levels.

But researchers at the University of British Columbia, Vancouver, and colleagues looked at the special problems of freshwater fish.

Only about 0.8% of the world’s water is fresh – that is, found in lakes and rivers – but freshwater species represent 40% of all fishes. Salmon spawn and the young are reared in fresh water, before taking to the seas to mature, then returning to repeat the cycle.

The Vancouver scientists report in Nature Climate Change that they tested very young embryos in water at acidity levels expected at the end of this century, and observed them for 10 weeks.

They found that these laboratory-reared salmon were smaller, and their ability to smell was reduced, which could mean problems in returning to their spawning grounds or for scenting danger and responding to it.

“It is not too late for society to benefit greatly from immediate reductions in CO2 emissions”

At the age of seaward migration, they were less able to use oxygen in their muscles, which promised problems finding food, evading predators or making long journeys.

“The increase in carbon dioxide in water is actually quite small from a chemistry perspective, so we didn’t expect to see so many effects,” said Michelle Ou, lead author of the study. “The growth, physiology and behaviour of these developing pink salmon are very much influenced by these small changes.”

Salmon aren’t the only freshwater fish at risk from climate change. Research published in the journal Environmental Toxicology and Chemistry reveals that a rise in water temperatures of 5°C could make common pesticides and industrial contaminants ever more toxic.

Ronald Patra, an environmental scientist at the Department of Planning and Environment in New South Wales, Australia, and colleagues tested rainbow trout, silver perch, rainbowfish and western carp gudgeon at temperatures higher than optimum for the species and in the presence of endosulfan, chlorpyrifos and phenol − all of which wash into waterways from the land.

Results varied according to pollutant, species and temperature, but, overall, all three chemicals became increasingly toxic as water temperatures rose.

Future toxicity

On the coast of Mangalore in southwest India, where mussel farming has become a growing industry, researchers decided to test future toxicity conditions for the green mussel.

The Society of Experimental Biology meeting in Prague learned that the bivalves were raised in high temperature and low salt conditions and exposed to toxic algae and bacteria of the kind that might be expected in a changing climate, which in turn affected the timing of the monsoon in ways that could lower seawater salinity.

“This is likely to increase the chance of outbreaks of toxic plankton blooms and make farming bivalves such as mussels increasingly challenging,” the meeting was told.

But changes to water chemistry – once again, the shift in pH values as yet more carbonic acid builds up in the seas – create problems enough for the commercial shellfisheries.

Wiley Evans, research associate at the Ocean Acidification Research Centre of the University of Alaska Fairbanks, and colleagues report in the Public Library of Science journal PLOS One that shellfish farmers off the Alaska coast might, at extra expense, have to start modifying the sea water in their hatcheries because, the researchers reported, they expect “significant effects” from acidification by 2040.

The scientists monitored for 10 months the effects of water chemistry changes on oyster, clam, scallop and other shellfish larvae.

Alaska – with a limited growing season, melting glaciers that affect salinity, and with colder waters that more readily dissolve carbon dioxide – is a special case.

But in general, as researchers have repeatedly found, increasingly corrosive waters would make it more difficult for shellfish to exploit the calcium carbonate minerals needed to make shells.

Shellfish spend their maturity in one spot, whereas fish can and do shift their grounds when the conditions become uncomfortable − with consequences for established commercial catches such as sardines and sea bass.

Likely to migrate

But a 5°C average warming in global atmospheric temperatures – and climate scientists have repeatedly warned that this is possible before 2100 – means that fish are likely to migrate away from their existing habitats considerably faster than they are doing now.

Jean-Pierre Gattuso, of the Oceanological Observatory in Villefranche, France, and colleagues looked at the evidence on a global scale and report in Science journal that, without attempts to mitigate global warming, the oceans and the creatures in them will be seriously affected by temperature changes and acidification.

This is very bad news for the millions of people in the communities that depend on the seas for a living.

“On a positive note, we still have options to substantially reduce these impacts now, but the longer we wait the fewer and fewer options we have,” warns co-author William Cheung, of the fisheries centre at Canada’s University of British Columbia.

Commenting on the research, Jason Hall-Spencer, a professor of marine biology at Plymouth University in the UK, said: “This review screams at me that the evidence is in, and it is not too late for society to benefit greatly from immediate reductions in CO2 emissions.” – Climate News Network

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Global warming threatens colder climate for Europe

Global warming threatens colder climate for Europe

New evidence that increased melting of sea ice as the Earth warms could weaken the Gulf Stream and reduce temperatures in western Europe.

LONDON, 3 July, 2015 – Scientists have yet again warned that weakening ocean circulation in the North Atlantic could deliver a climate paradox − a colder Europe as a consequence of global warming.

A study published in Nature Climate Change found that as sea ice off Iceland and Greenland retreats, the flow of cold, dense water to the bottom of the North Atlantic ocean could be reduced, and therefore weaken the warming effects of the Gulf Stream.

The great submarine current − sometimes called the Atlantic Conveyor − flows south to surface in the tropics as the Gulf Stream, which then flows north again to deliver tropic warmth to European coasts.

However, a slowdown in the natural overturning of the ocean could weaken the Gulf Stream, which in turn could cool the atmosphere over the British Isles and western Europe.

“A warm western Europe requires a cold North Atlantic, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over Western Europe,” says Kent Moore, a professor of physics at the University of Toronto Mississauga, Canada.

Calamitous change

Such a possible collapse of a natural oceanic system is predicated as one of the irreversible tipping points that could result in calamitous climate change.

Scientists have twice warned in the past six months that such change could be irreversible, unless governments jointly decide to dramatically reduce greenhouse gas emissions from the combustion of fossil fuels by switching to renewable sources of energy.

Another research group reported in March this year on how the changing salinity of the northern ocean waters − because of the increasing flow of meltwater from land-borne glaciers − threatened a weakening of the Atlantic Conveyor.

“The heat exchange is weaker – it’s like turning down the stove 20%”

In the latest study, Professor Moore and colleagues from Norway, the US and the UK looked not at changes in ocean salinity, but at the exchange of heat between sea and air.

Climate is driven by contrasts, and the flow of heat between water and wind in winter has weakened by around 20% since 1979. The Arctic is the fastest-warming region of the planet, and changes in the polar climate can have dramatic consequences for the temperate zones.

Prof Moore and his colleagues looked at wintertime data from the Iceland and Greenland Seas between 1958 and 2014, then used computer simulations to model potential changes to the Conveyor − more formally known to oceanographers and climate scientists as the Atlantic Meridional Ocean Circulation.

Cold and salty

The warm current loses its heat to the atmosphere as it moves north, and water that is both cold and salty is denser and more likely to descend.

The most effective place for such a process to happen is at the edge of the sea ice. If the sea ice retreats, then so does the region of maximum heat exchange. For the past 10,000 years or so, this heat exchange has happened at the ideal spot for surface waters to sink. Any change might not be for the better.

The Gulf Stream is the agency that makes Britain, for example, about 5°C warmer than Labrador in Canada, on the same latitude. A British government chief scientific adviser once calculated that the Gulf Stream delivered the warmth of 27,000 power stations. So if it weakens, Europe could start to feel the chill.

“The heat exchange is weaker – it’s like turning down the stove 20%,” Prof Moore says. “We believe the weakening will continue and eventually cause changes in the Atlantic Meridional Overturning Circulation and the Gulf Stream, which can impact the climate of Europe.” – Climate News Network

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Greenhouse gas-guzzlers spurn extra carbon dioxide

Greenhouse gas-guzzlers spurn extra carbon dioxide

Minutely small marine plants called diatoms mitigate climate change by consuming carbon dioxide and producing oxygen. But they may reject the rising levels of the greenhouse gas.

LONDON, 1 July, 2015 – Diatoms – those tiny ocean-dwelling photosynthesisers that produce a fifth of the planet’s oxygen each year – may not gulp down more carbon dioxide more enthusiastically as greenhouse gas levels in the atmosphere continue to rise.

Instead, they may switch off and use the gas more efficiently. If so, the consequences for the rest of the planet could be uncomfortable.

Climate scientists who try to model the machinery of the atmosphere have always banked on a “fertilisation effect” from at least some of the extra CO2 pumped into the atmosphere by the human burning of fossil fuels and the clearance of the forests. They may no longer be able to do so.

The discovery – reported in Nature Climate Change – is based on laboratory experiments with one single-celled phytoplankton species called Thalassiosira pseudonana and meticulous study of its genetic mechanisms.

Rising concentrations

It may not be a sure guide to what actually happens in the crowded, complex world of climate change later this century. But all phytoplankton are survivors of the same evolutionary history, and many of them are known to be equipped with carbon-concentrating mechanisms to make the most of the available carbon dioxide in the atmosphere. So what happens to one could be true for all.

Gwenn Hennon, an oceanographer at the University of Washington in Seattle, US, and colleagues decided to work out what happened to their laboratory diatoms in atmospheres in which carbon dioxide levels continued to rise to 800 parts per million later this century.

Right now, the concentration is almost 400 parts per million, but for most of human history until the invention of the internal combustion engine, and the exploitation of fossil fuels, it has been around 280 parts per million. A third of the emissions from factory chimneys and motor exhausts is absorbed by living things in the oceans, starting with diatoms and other phytoplankton.

The Seattle team found that while many photosynthesisers do grow faster with more CO2, the oceanic diatoms did not: they responded vigorously at first, but as long as there was a normal supply of other nutrients, over 15 generations, they slowed down.

Slow response

“There are certain genes that respond right away to a change in CO2, but the change in the metabolism doesn’t actually happen until you give the diatoms some time to acclimate,” said Hennon, a doctoral student. “Instead of using that energy from the CO2 to grow faster, they just stopped harvesting as much energy from light through photosynthesis and carried out less respiration.”

Studies like this are an illustration of the intricacy and complexity of climate science. How the living world responds to greater human emissions of carbon dioxide from fossil fuels is key to all models of future climates, but researchers in general have expected the plant world to respond by consuming more, and slowing the rate of change overall.

There is some evidence that this is happening. Half of all the anthropogenic or human-made CO2 has been gulped down in the form of more lusty growth by vegetation, but this “negative feedback” effect has been countered by other factors: more greenery in the Arctic, for instance, could accelerate global warming, and anyway, as plants grow more vigorously, so do plant predators.

And increasingly, climate scientists have begun to realise that although the responses of the forests and arid lands  are vital factors, the big players could be the creatures hardly anyone ever sees: the fungi and tiny fauna in the soil  beneath the trees, and of course the phytoplankton in the oceans.

Oxygen creators

The Seattle calculation is that the evolutionary history of the diatoms explains the carbon-concentrating mechanisms in their genetic inheritance. Microbes are life’s foundation, and single-celled creatures evolved over three billion years when CO2 levels in the atmosphere were at colossal concentrations.

The diatoms and their ancestors were the creatures that created the oxygen atmosphere in which all other complex living things evolved. An enzyme evolved to help the first microbes cope with high levels of CO2, and has survived for billions of years.

“There hasn’t been another enzyme to replace it since, so plants and algae that photosynthesise have an enzyme that functions better at a higher CO2 level than we currently have,” Hennon said.

“When the CO2 remains high for a long time, however, the diatoms make a more radical metabolic shift. They decrease photosynthesis and respiration to balance the cell’s energy budget. In other words, the diatoms use less energy to grow at the same rate.” – Climate News Network

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Scientists detect mysterious warming in US coastal waters

Scientists detect mysterious warming in US coastal waters

Unprecedented ocean temperature rises off the Atlantic and Pacific coasts of the US may be linked to sea level rise or the recent pattern of “weird” weather.

LONDON, 28 June, 2015 − Oceanographers are puzzled by an accelerated burst of warming sea that threatens the fisheries of the American Atlantic coast.

Meanwhile, off the US West coast, scientists report that they have been baffled by a mysterious “blob” of water up to 4°C warmer than the surrounding Pacific, linked to weird weather across the entire country.

Jacob Forsyth and research colleagues from the Woods Hole Oceanographic Institution (WHOI) in Massachusetts report in the Journal of Geophysical Research: Oceans that the ocean off the US north-east continental shelf has been warming at unprecedented levels for 13 years.

Their findings came after analysis of data from sensors − called bathythermographs − dropped 14 times a year from the container ship Oleander, which for 37 years has travelled between New Jersey and Bermuda. Each detector takes the temperature of the water column as it sinks up to 700 metres.

Startling discovery

What they were startled to discover was an unexplained, and unprecedented, rise in the water temperatures that may be linked with an equally mysterious sea level anomaly: sea levels are going up, but they are going up faster off the north-east coast of the US than almost anywhere else.

“The warming rate since 2002 is 15 times faster than from the previous 100 years,” says Glen Gawarkiewicz, a WHOI senior scientist and one of the authors of the report.

“There’s just been this incredible acceleration to the warming, and we don’t know if it’s decadal variability or if this trend will continue.”

“It’s producing conditions that we think are going to be more common with global warming”

To make sure of their perspective, the authors compared their analysis with surface data from the Nantucket lightship and other such installations along the coast, from 1880 to 2004. The new study shows that the warming is not just confined to surface waters.

Although there must be some link with the steady rise in atmospheric temperatures because of global warming as a result of human-made carbon dioxide emissions, the oceanographers suspect there may also be another explanation, so far undiscovered.

Off the Pacific coast, meteorologists have been scratching their heads over the appearance in 2014 of a “remarkably” warm patch −  1,500 kilometres across in every direction and 100 metres deep − that could be linked to “weird” weather across the continental US that has seen heat and drought in the west and blizzards and chills in the East.

High pressure ridge

Nicholas Bond,  a research meteorologist at the University of Washington in Seattle, and colleagues report in Geophysical Research Letters that what they have called “the blob” was linked to a persistent high pressure ridge, linked in turn to a calmer ocean during the last two northern hemisphere winters.

The blob plays a sure role in the West Coast weather. Air sweeping across it picks up heat, and this results in warmer temperatures and lower snowpack in coastal mountains − which certainly stoke up the conditions for drought.

A second study in Geophysical Research Letters links the warm Pacific puzzle to the big freeze in the eastern states in 2013 and 2014.

Once again, there doesn’t seem to be a direct connection with climate change, but it raises the spectre of changes to come.

“This is a taste of what the ocean will be like in future decades,” Dr Bond says. “It wasn’t caused by global warming, but it’s producing conditions that we think are going to be more common with global warming.” − Climate News Network

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Global warming means double jeopardy for sea life

Global warming means double jeopardy for sea life

Some sea creatures seeking to escape warming oceans as the mercury rises will find that climate change is damaging the areas which could give them refuge.

LONDON, 9 June, 2015 − Global warming is likely to drive marine creatures away from the equator in search of new and cooler habitats − and  is likely to limit the safest options for many migrant fish, crabs and corals.

One problem for marine life is that warmer waters hold less oxygen, so the corals that move to higher latitudes will have to settle in shallower water to take advantage of the diminishing light. This, too, creates hazards.

Curtis Deutsch, an oceanographer at the University of Washington in the US, and colleagues report in the journal Science that the ocean’s denizens could be heading for respiratory stress. Warmer waters speed up the metabolic need for oxygen, but those same warmer waters hold lower levels of dissolved gases.

“If your metabolism goes up, you need more food and you need more oxygen,” Dr Deutsch says. “This means that aquatic animals could become oxygen-starved in the warmer future, even if oxygen doesn’t change. We know that oxygen levels in the ocean are going down now, and will decrease more with climate warming.”

Shifting habitats

His co-author, Hans-Otto Pörtner, head of the Department of Integrative Ecophysiology at the Alfred Wegener Institute in Bremerhaven, Germany, says: “If the oxygen level in a given region of the ocean drops below a species’ minimum requirements, it forces the animals to abandon their native habitat. This combines with the effect of warmer temperatures.

“Since animals evade to cooler regions, their habitat shifts towards the poles or to greater water depths. In Atlantic cod and many other fish species, we can already observe the shift now.”

That change is undoubtedly on the way. One group has just calculated that between 50% and 70% of the world’s oceans could see changes in biodiversity as the sea surface temperatures creep upwards.

The next question is: what kinds of change and what kinds of habitat will be available for submarine climate refugees? The researchers chose four well-studied marine species for their simulations of the impact of climate change on the maritime world.

Combined stress

These are the open ocean-dweller Atlantic cod, the coastal water-dwelling Atlantic rock crab, the sharp snout sea bream of the sub-tropical Atlantic and Mediterranean, and the common eelpout, a bottom-dwelling fish that lives in the shallow waters of the high northern latitudes.

The study suggests that, for many species, the combined stress of higher metabolic rates and lower levels of dissolved oxygen will mean that possible habitats will contract by between 14% and 26% because at the present species’ ranges nearer the equator, peak oxygen demand would become greater than the supply.

Also in Science journal, a team led by Paul Muir, acting curator for corals at the Museum of Tropical Queensland in Australia, reports on the potential future for 104 species of staghorn corals – the tiny creatures whose skeletons make up the reefs that offer the richest habitats in the tropical seas.

Corals are sensitive to extremes of temperature. As the mercury levels climb, they can “bleach” and reject the algae on which they depend for survival. And if conditions are too hot for too long, they can perish.

Little sunlight

But the Australian team found that these animals, too, are caught in a kind of habitat trap. As they migrate away from the equator, they must nest in shallower water to take advantage of the lower levels of winter sunlight that penetrate the waters at higher latitudes.

The corals are likely to have to rise 0.6 metres for every one degree of latitude of migration. But there is a limit to how high in the water they can rise because, at a certain point, temperature, salinity and wave damage will start to take their toll.

“The two studies remind us that climate change will reshape marine species’ habitats, but not necessarily expand them,” warns Joan Kleypas, a marine ecologist/geologist at the US National Centre for Atmospheric Research, in the same journal.

“Both studies highlight little-recognised barriers to future range expansions in the oceans,” he says. “Each is based on physiological limitations of marine organisms that are quantifiable, and thus increase our ability to predict species habitats into the future.” − Climate News Network

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Earth has warmed as usual, with no slowdown

Earth has warmed as usual, with no slowdown

US scientists re-examine the collection of data which seemed to show global warming slowing since 1998 and say temperatures have continued to rise steadily.

LONDON, 7 June, 2015 − Forget about the so-called “hiatus” in global warming. The planet’s average temperatures are notching up as swiftly now as they did 20 or 30 years ago.

A team of US researchers has looked again not just at the data for the last 60 years but at how it has been collected, and done the sums again. They conclude, in the journal Science,  that the “estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century. These results do not support the notion of a ‘slowdown’ in the increase of global surface temperature rise.”

But first, the story-so-far. Climate sceptics have repeatedly claimed that global warming has slowed or stopped. This was not the case: 13 of the hottest years ever recorded have all occurred in the last 14 years, and 2014 was the hottest of them all.

But when climate scientists looked at a graph of the rise of temperatures in the last 60 years, they saw – or thought they saw – a distinct drop in the rate of increase in global average temperatures in the last 15 years.

This apparent dip became the subject of a whole series of studies. Researchers had never expected the rise to follow a straight line – all sorts of natural climate cycles would naturally affect annual records – but the rate of increase was slower, and more sustained in its slowness, than anyone could explain, especially as there had been no drop in the greenhouse gas emissions that drive global warming.

Data anomalies

Some proposed that the expected extra heat in the atmosphere had been drawn down into the great oceans and others that an unnoticed increase in volcanic activity had helped screen the sunlight and cool the atmosphere unexpectedly. Yet another group looked not at average temperature patterns but the change in the frequency of heat waves and saw a different kind of rise.

Yet another group wondered if the problem might be only apparent: more complete data from many more parts of the world might combine to tell a different story. Thomas Karl and colleagues at the National Oceanographic and Atmospheric Administration in the US made this their starting point.

They looked again at how the data had been collected, and the gaps that might have appeared. Sea surface temperatures, for instance, were at different periods collected by bucket from a ship’s deck, by readings aboard surface drifting and moored buoys or by engine-intake thermometers in ships’ engine rooms, and there could be subtle differences not accounted for.

There were very few readings from the Arctic, yet the Arctic is by far the fastest-warming region of the planet, and the pattern of land-based temperature readings, too, repaid re-examination.

By the time the NOAA team had finished, the recalibrated figures told a different story. Between 1998 and 2012, the world warmed at the rate of 0.086°C per decade, more than twice the rate of 0.039°C per decade measured by the Intergovernmental Panel on Climate Change.

“We need to look really carefully at data quality and issues of instrument change”

The new figure is much closer to the rate estimated for the decades 1950 to 1999, at 0.113°C per decade. And the new analysis lifts the rate of warming from 2000 to 2014 to 0.116°C per decade, which if anything is an acceleration, not a slowdown.

British climate scientists have welcomed the finding: it is however the finding of just one group and, like all such research, will be accepted more readily if it can be separately replicated.

“This study makes the important point that we need to look really carefully at data quality and issues of instrument change,” said Piers Forster, professor of climate change at the University of Leeds, UK.

”Yet there are several legitimate judgment calls made when combining datasets to make a global mean-time series. I still don’t think this study will be the last word on this complex subject.”

But Peter Wadhams, a professor of ocean physics at the University of Cambridge, UK, called the study careful and persuasive, and said: “I think it shows clearly that the so-called ‘hiatus’ does not exist and that global warming has continued over the past few years at the same rate as in earlier years.” − Climate News Network

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Climate change could treble risks for marine life

Climate change could treble risks for marine life

Scientists warn that even stabilised levels of fossil fuel use could cause changes to ocean ecosystems far greater than any witnessed in the last 50 years.

LONDON, 4 June, 2015 − Severe global warming – a rise in annual average global temperatures driven by ever-increasing burning of fossil fuels – could force change in up to 70% of the ocean ecosystems, according to new research.

Even moderate global warming, in which greenhouse gas emissions stabilise in the next 25 years, could trigger changes three times greater than any seen in oceans over the last 50 years.

Marine biologist Grégory Beaugrand, of the University of Science and Technology at Lille in France, and colleagues report in Nature Climate Change that they used a new approach to calculate the overall pattern of winners and losers in tomorrow’s world, as carbon dioxide levels in the atmosphere soar and climates change.

They found that tropic and warm water regions would become poorer in living things, with biodiversity decreased. Some species would become extinct, some might adapt, and others would migrate.

Higher latitudes, however, would see a greater mix of living creatures – an increase in diversity of up to 300% – as species migrated north or south towards the polar regions in response to sea temperature change.

Ground-breaking model

The scientists started from the basis that − local variations in fishing, hunting, food supply and water chemistry aside − what mattered in the marine world was mostly temperature.

“We developed a ground-breaking new model for how biodiversity is arranged in the oceans and tested its accuracy using real world examples from plankton to whales − in fact the smallest of sea creatures to the largest,” Dr Beaugrand says.

“The main environmental variable in our model influencing where species like to live is temperature. We demonstrated that our model can reconstruct accurately patterns of marine biodiversity, and then we used it to see how biodiversity may reorganise in response to four different levels of global warming.”

The scientists used the past as a guide to the present and to future change. They compared the distribution of species now with what the fossil record showed for the mid-Pliocene epoch about  three million years ago, when the world was 3°C warmer than it is now, and during the last glacial maximum 20,000 years ago, when the world was 4°C to 5°C cooler.

“Any changes in biodiversity will inevitably affect interactions among species, and consequently how the ecosystem functions”

The researchers from France, Britain and Monaco have once again confirmed that the warmer the planet, the greater the potential change. But most previous research has focused on the impact of climate change on the terrestrial world. In fact, Earth is 70% ocean, and 70% of the planet’s people live within 60km of the shoreline.

Humans survive on the sea’s productivity, landing 80 million tonnes of fish each year, and the oceans play a decisive role in the regulation of the planetary climate.

The oceans have already begun to respond to climate change, as familiar species move north or dive deeper in search of the ideal temperatures in which to thrive, and invasive species eat away at long-established ecosystems.

But it is harder to predict quite how nature rebalances itself in oceans that will also be changed by increasing acidity and pollution.

“Any reorganisation of marine biodiversity will affect us in some way,” Dr Beaugrand says. “Some individual changes may be good, and some may be bad. For example, harmful algal blooms may increase in some places and decrease in others.

Function and productivity

“However, together, any changes in biodiversity will inevitably affect interactions among species, and consequently how the ecosystem functions and how productive it is, which are important aspects to understand and predict.”

If the world’s nations keep to the commitment to limit global warming to below 2°C, only about 15% of the ocean would undergo changes greater than happened over the last 20,000 years, and only 25% would see a change greater than since the mid-Pliocene more than  three million years ago.

However,  at 2°C, between 37% and 46% of the oceans would experience changes in biodiversity, and at higher levels these changes could range from 50% to 70%, the scientists say.

If emissions peak in the next five years and begin to decline, any biological changes might not be very different from existing patterns of variability seen in the last 50 years. But change is on the way.

“Our results show that climate change may rapidly reorganise marine biodiversity over large oceanic regions, and that the intensity of this reorganisation will depend, unsurprisingly, on the magnitude of warming,” the authors conclude. – Climate News Network

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