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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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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Small volcanic eruptions are key to warming hiatus

Small volcanic eruptions are key to warming hiatus

Sulphur dioxide hurled in vast amounts from volcanoes is known to cool the atmosphere, but now scientists have identified how even small eruptions have a big effect on climate.

LONDON, 13 January, 2015 − Researchers now have a new explanation for the so-called slowdown in global warming in this century. They blame it on not very dramatic, small-scale volcanic eruptions.

This is a new twist in a puzzling story. In 1991, a catastrophic eruption of Mount Pinatubo in the Philippines hurled 20 million tonnes of sulphur dioxide into the stratosphere − a delivery of aerosols huge enough to block incoming sunlight and actually cool the planet for a couple of years. The assumption since then has been that big volcanic eruptions have enough heft to influence climate.

But in two recent papers, researchers have proposed another hypothesis, and then identified the evidence that a greater number of quite modest eruptions could have the same effect.

Mechanisms at work

To demonstrate such a thing, scientists need to pinpoint the mechanisms at work. In November, David Ridley, an atmospheric scientist at the Massachusetts Institute of Technology, and colleagues focused on the intersection of two atmospheric layers – the atmosphere and troposphere.

They used a mix of ground, air and space-based technology to observe the aerosols in the lower stratosphere, and then they played with a climate model. The conclusions were straightforward: volcanoes could have caused a cooling of between 0.05°C and 0.12°C since 2000.

And the latest study, by a team led by Benjamin Santer, an atmospheric scientist at the Lawrence Livermore National Laboratory in California, has shown that the “signals” of eruptions in the late 20th and early 21st centuries can be positively identified in the atmospheric temperature, moisture and reflected radiation at the top of the atmosphere.

This signal, they report in Geophysical Research Letters, doesn’t explain all the hiatus or slowdown. But it makes a significant contribution.

Uptick in activity

Very roughly, there are 1,500 active volcanoes on the planet and, during 1990, there were 53 recorded eruptions. In 2010, there were 83; in 2013, there were a record 84. So it looks as if an uptick in geothermal activity could have made a difference.

But the climate machine is not a simple thing, and the argument is likely to go on. Other researchers have proposed that the missing heat is concealed in the ocean depths, or that a change in the trade winds may be a factor, or that climate scientists may have misread the signals because the extremes in the last 15 years have been hotter, even if the average has not increased much.

So, all along, the discussion has been not just about what might have been missed, but also about precisely what should or could be measured. And, in any case, words such as “pause”, “hiatus” and even “slowdown” add to the confusion.

Early in December, meteorologists declared 2014 on course to be the warmest year ever. It may not prove so – the calculations will take a few more weeks – but even if it isn’t, 14 of the 15 warmest years ever recorded have all occurred in the 21st century. – Climate News Network

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Trapped methane escapes as Pacific depths warm up

Trapped methane escapes as Pacific depths warm up

Oceanographers in the US warn that volumes of methane equivalent to a major oil spill are rising to the surface each year as warmer waters heat the frozen ocean bed.

LONDON, 11 January, 2015 – Researchers studying methane trapped in frozen layers below the Pacific Ocean seafloor predict that more and more of the potent greenhouse gas could bubble towards the surface as the deep water begins to warm.

“We calculate that methane equivalent in volume to the Deepwater Horizon oil spill [in 2010] is released every year off the Washington coast,” says Evan Solomon, assistant professor at the University of Washington School of Oceanography in the US.

Methane hydrates are the natural gas methane in solid form. Volume for volume, methane is at least 20 times more potent a greenhouse gas than carbon dioxide, although it is released in smaller quantities and has a much shorter lifespan in the atmosphere.

Vast quantities of the stuff are known to be trapped in sedimentary rocks and in the sea bed, in “frozen” form − held by a combination of temperature and pressure.

Fastest warming

Until now, most of the focus has been on the methane hydrates in the Arctic, the fastest warming region on the planet.

But Dr Solomon, oceanographer and lead author Susan Hautala and colleagues report in Geophysical Research Letters their calculations that between 1970 and 2013, some 4 million tonnes of methane have been released from the sea floor off the coast of Washington state.

This is about the equivalent of the natural gas released in 2010 when the Deepwater Horizon oil well blew out off the coast of Louisiana, and 500 times the rate of natural release from the sea floor.

Coring machine used to gather sediment samples from the Pacific. Image: Robert Cannata/University of Washington

Coring machine used to gather sediment samples from deep in the Pacific Ocean.
Image: Robert Cannata/University of Washington

The Pacific Northwest has high rates of biological activity, and methane is a natural biological product. At high ocean pressures and low sea temperatures, it “freezes” or crystallises in a solid state. And because the waters of the Pacific Northwest have been so rich in life, the seabed below is rich in methane hydrates.

But ocean waters have started to warm, at depth, and currents have carried the warming water across the ocean to the North American shelf.

Atmospheric warming

As water warms, the submarine methane “ice line” retreats further offshore − rather in the way that a snowline moves up hill, or a glacier retreats, in response to atmospheric warming.

The Washington scientists calculate that, since 1970, the boundary at which methane stays frozen has retreated by about a kilometre. By 2100, it will have moved perhaps another three kilometres off shore.

Their calculations suggest that, by the century’s end, 400,000 metric tonnes a year will escape. And the puzzle now is where the released methane will end up.

Some could be consumed by methane-eating bacteria in the seafloor ooze. But fishermen have also observed the stuff bubbling to the surface, to add to the burden of atmospheric greenhouse gases.

The finding, the researchers say, has “worldwide implications” for other oceanic reservoirs of the stuff, close to continental shelves and therefore vulnerable to large-scale melting. – Climate News Network

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Ocean warming speeds up cycle of climate change

Ocean warming speeds up cycle of climate change

British and German scientists have identified another consequence of global warming that is likely to accelerate climate change still further.

LONDON, 9 January, 2015 − The warming oceans could start to return more carbon dioxide to the atmosphere as the planet warms, according to new research.

And since 70% of the planet is covered by clear blue water, anything that reduces the oceans’ capacity to soak up and sequester carbon could only make climate change more certain and more swift.

It is a process that engineers call “positive feedback”. And under such a cycle of feedback, the world will continue to get even warmer, accelerating the process yet again.

Many such studies are, in essence, computer simulations. But Chris Marsay − a marine biochemist at the UK’s National Oceanography Centre in Southampton − and colleagues based their results on experiments at sea.

Sediment traps

They report in the Proceedings of the National Academy of Sciences that they examined sediment traps in the North Atlantic to work out what happens to organic carbon – the tissue of the living things that exploit photosynthesis, directly or indirectly, to convert carbon dioxide – as it sinks to the depths.

Sooner or later, much of this stuff gets released into the sea water as carbon dioxide. This is sometimes called the ocean’s biological carbon pump. In deep, cold waters, the process is slow. In warmer, shallower waters, it accelerates.

And as there is evidence that the ocean is responding to atmospheric changes in temperature, both at the surface and at depth, the study suggests that “predicted future increases in ocean temperatures will result in reduced CO2 storage by the oceans”.

The research was conducted on a small scale, in a limited stretch of ocean, so the conclusion is still provisional − and, like all good science, will be confirmed by replication. But it is yet another instance of the self-sustaining momentum of global warming.

Such positive feedbacks are already at work in high latitudes. Ice reflects sunlight, and therefore the sun’s heat. So as the Arctic ice sheet steadily diminishes over the decades, more and more blue water is available to absorb heat − and accelerate warming.

“The world is at a crossroads in terms of climate health and climate change”

The same gradual warming has started to release another greenhouse gas trapped at the ocean’s edge. Natural “marsh gas”, or methane, is stored in huge masses, “frozen” as methane hydrate in cold continental shelves.

Methane exists in much smaller quantities than carbon dioxide, and has a shorter life in the atmosphere, but is far more potent, volume for volume, as a greenhouse gas.

Researchers at the Arctic University of Norway in Tromso reported last month in Geophysical Research Letters that once-frozen methane gas was leaking from thawing ocean floor off Siberia. Some of this thaw is natural, and perhaps inevitable. But some is connected with human influence and could accelerate.

Alexei Portnov, a geophysicists at the university’s Centre for Arctic Gas Hydrate, Climate and Environment  says: “If the temperature of the oceans increases by two degrees, as suggested by some reports, it will accelerate the thawing to the extreme. A warming climate could lead to an explosive gas release from the shallow areas.”

Biological origin

Arctic methane, like ocean organic carbon, has a biological origin. It is released by decaying vegetation under marshy conditions and tends to form as a kind of ice at low temperatures and high pressures, much of it along continental shelves that, at the height of the Ice Ages, were above sea level.

The International Union for Conservation of Nature also reminded the world last month that the ocean plays a vital role in climate, and that plankton, fish and crustaceans could be considered as “mobile carbon units”.

In this sense, the fish in the sea are not just suppers waiting to be caught, but are important parts of the planetary climate system. The healthier the oceans, and the richer they are in living things, the more effective they become at soaking up atmospheric carbon.

“The world is at a crossroads in terms of climate health and climate change,” said Dan Laffoley, vice-chairman of the IUCN World Commission on Protected Areas, introducing a new report on the marine role in the carbon cycle.

“Neglect the ocean and wonder why our actions are not effective, or manage and restore the ocean to boost food security and reduce the impact of climate change. The choice should be an easy one.” – Climate News Network

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US coastal cities warned of daily high tide floods

US coastal cities warned of daily high tide floods

Scientists report that many cities near the coasts of the US should prepare for daily flooding at high tide by mid-century because of rising sea levels.

LONDON, 5 January, 2015 − Oceanographers have just identified the US coastal regions likely to experience 30 days or more of “nuisance” flooding every year. And the answer is that most of the American coast will experience high waters that are 30-60 cms above local high tides, at least 30 times a year.

Nuisance flooding means just that − somewhere between an inconvenience and modest damage. But climate change, and its attendant sea-level rise, will make them much more frequent, and possibly more damaging.

William Sweet and Joseph Park, scientists at the National Oceanic and Atmospheric Administration (NOAA), report in the journal Earth’s Future that sea level rise has accelerated from 1.7mm a year in the last century to 3.2mm a year in the last two decades, and flooding events that were once extreme could become the mean.

The oceanographers wanted to establish what they call “regional tipping points” – places where extra high waters would wash across streets and promenades normally above water and start to do so frequently.

Detailed picture

New York was inundated when Superstorm Sandy hit the city in 2012, and studies have repeatedly warned that coastal inundations will cost communities colossal sums each year by 2050, and even more by 2100. Nor is the US alone in this respect. There have been ominous calculations for the UK as well.

The NOAA scientists add detail to the big picture. They started with the projections for global sea level rise delivered by the Intergovernmental Panel on Climate Change and then included the more local factors such as land subsidence or settlement, and cyclic weather patterns that exacerbate the tidal highs. Such floods have already increased, and are now five to 10 times more likely than 50 years ago.

They looked at all those tidal stations with a continuous 50-year record of measurement. This does not include the city of Miami, where the tide stations were destroyed in 1992 by Hurricane Andrew.

Coastal changes

And they warn that Boston, New York City, Philadelphia, Baltimore and many other places along the Atlantic Coast, Galveston and Port Isabel in the Gulf of Mexico, and San Francisco Bay and San Diego along the Pacific Coast will all see a lot more seawater in city streets.

“Coastal communities are beginning to experience sunny-day nuisance flooding, much more so than in decades past,” said Dr Sweet. “This is due to sea level rise.

“Unfortunately, once impacts are noticed, they will become commonplace rather quickly. We find that in 30 to 40 years, even modest projections of global sea level rise – 1.5 feet by the year 2100 – will increase instances of daily high tide flooding to a point requiring an active and potentially costly response.

“And by the end of the century, our projections show that there will be near-daily nuisance flooding in most of the locations that we reviewed.” – Climate News Network

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Scientists track natural responses to climate change

Scientists track natural responses to climate change

Researchers in the US have identified a wide range of impacts – human and natural – that global warming has on fish, forests, birds and wildflowers.

LONDON, 31 December, 2014 − Lumberjacks are selecting different trees, US fishermen are sailing further north to catch black sea bass, desert birds are nesting later in California and Arizona, and one kind of wildflower is changing shape in the Rocky Mountains − and all in response to climate change, according to new research.

None of these responses is simple, or necessarily ominous, and global warming is not the only factor at work. But all are nevertheless examples of adaptation to − so far – very modest changes in temperature.

Adena Rissman and Chad Rittenhouse, of the University of Wisconsin-Madison, report in the Journal of Environmental Management that they looked at weather records and logging data and found that, since 1948, the winter interval during which ground is firmly frozen has declined by an average of two to three weeks.

Hard winters are the logger’s friend as the ground can support heavy machinery, whereas muddy soils can make tracks impassable. So, over the decades, foresters have harvested more and more red pine and jack pine − species that flourish in sandy, well-drained soil more accessible to trucks, tractors and chainsaws.

Significant decline

“We wanted to know how weather affects our ability to support sustainable working forests,” says Dr Rissman, assistant professor of human dimensions of ecosystem management. “We found a significant decline in the duration of frozen ground over the past 65 years and, at the same time, a significant shift in the species being harvested.”

Such changes in selection tend to affect ecosystems – on land or at sea.

Scientists at the Northeast Fisheries Science Centre in the US report in the ICES Journal of Marine Science that they looked at trawl survey data collected between 1972 and 2008 to analyse variations in abundance of black sea bass, scup, and summer and winter flounder. All had shown “significant poleward shifts” in at least one season.

“We demonstrated how a combination of fishing and climate can influence the distribution of marine fish”

The bass and scup were responding to changes in temperature. The summer flounder were more likely to be responding to a decrease in fishing pressure − that is, the species could recolonise former habitat. There was no change in the distribution in the southern New England/Mid Atlantic Bight stock of winter flounder.

“Using these data, we demonstrated how a combination of fishing and climate can influence the distribution of marine fish,” said lead author Richard Bell, research associate at the US National Oceanic and Atmospheric Administration fisheries service laboratory at Narrangansett.“It is not one or the other.”

Meanwhile, in the arid American southwest’s Sonora Desert, all 13 desert bird species have tended to delay nesting by two weeks or more, as a response to severe drought.

Delays in nesting

This makes survival a problem for the birds as their young are more vulnerable to nest predators and parasites. Some species forego breeding entirely during an extreme drought. Even without global warming, droughts are an enduring fact of life in the region. But ecologists point out that climate models predict a greater frequency of droughts, which could lead to even more delays in nesting.

“These responses are predicted to become more frequent and extreme, due to climate change, causing us to question how desert birds will persist in the long term,” Chris McCreedy, a desert ecologist at Point Blue Conservation Science, reports in The Auk, the American Ornithologists’ Union journal.

The hardy Rocky Mountain mustard plant Image: USDA via Wikimedia Commons

The hardy Rocky Mountain mustard plant
Image: USDA via Wikimedia Commonse

At least one species has responded to climate change by altering not just its life cycle but its shape.

Students at Dartmouth College in New Hampshire and the University of South Carolina report in Global Change Biology that the Rocky Mountain mustard plant (Boechera stricta) offers an example of what biologists call “phenotypic plasticity”.

This means that it doesn’t evolve to meet climate change − it just looks different under different conditions. It changes according to whether the conditions are hot and dry, or cold and wet. In experiments that simulated future climate change, it also flowered seven days earlier.

This little ready-for-anything brassica plant seemed able to respond differently according to whether or not there was snow around it. Or, as the researchers put it: “Extensive plasticity could buffer against immediate fitness declines due to changing climates.” – Climate News Network

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Polar bears feel the heat as frozen habitat shrinks

Polar bears feel the heat as frozen habitat shrinks

As climate change increasingly affects the Arctic, some polar bear populations are suffering because rising temperatures are reducing the sea ice vital for their survival.

LONDON, 19 December, 2014 − The Arctic is changing faster under the influence of the warming climate than anywhere else on Earth, scientists have confirmed.

The US National Oceanic and Atmospheric Administration (NOAA) says Arctic air temperatures continue to rise more than twice as fast as they do globally − a phenomenon known as Arctic amplification.

The extent of snow cover in April 2014 in Eurasia was the lowest since 1967, and sea ice extent in September was the sixth lowest since 1979.

Badly affected

Some Arctic polar bear populations have been badly affected by the progressive shrinking of Arctic sea ice.

But NOAA says: “Natural variation remains, such as the slight increase in March 2014 sea ice thickness and only a slight decrease in total mass of the Greenland ice sheet in summer 2014.”

Increasing air and sea surface temperatures, a decline in the reflectivity of the ice at the surface of the Greenland ice sheet, shrinking spring snow cover on land and summer ice on the ocean, and the declining populations and worsening health of some bear populations are among the findings described in NOAA’s Arctic Report Card 2014.

“Arctic warming is setting off changes that affect people and the environment in this fragile region, and has broader effects beyond the Arctic on global security, trade and climate,” Craig McLean, of NOAA, told the annual American Geophysical Union Fall meeting in San Francisco.

“This year’s Arctic Report Card shows the importance of international collaboration on long-term observing programmes that can provide vital information to citizens, policymakers and industry.”

“Arctic warming has broader effects beyond the Arctic on global security, trade and climate”

The Report Card, published annually since 2006, updates changes affecting the Arctic. This year’s report − written by 63 US and other authors − covers key indicators, and also includes a new report on the status of the bears.

This section, written by the Norwegian Polar Institute and Polar Bears International, assesses the animals’ populations in some areas where there is good long-term data available. There are clear variations between areas.

Ice break-up

The most recent data shows that a population decline in western Hudson Bay, Canada, was caused by earlier sea ice break-up and later freeze-up.

The bears depend on sea ice to travel, hunt, mate and, in some areas, to den. But in the southern Beaufort Sea, north of Alaska, their numbers have now stabilised after a decline of about 40% since 2001.

In the Chukchi Sea, between Alaska and Russia and immediately to the west of the Beaufort, the condition of the bears and their reproductive rates have been stable for 20 years.

The Report Card says there are now twice as many ice-free days in the southern Beaufort as there are in the Chukchi Sea.

It notes that polar bears have been through “long and dramatic periods of population decline” during the last million years, and that during periods with little sea ice, polar bears and brown bears have often interbred.

The report says Alaska recorded temperature anomalies more than 10°C higher than the January average during 2014.

Snow cover across the Arctic during the spring was below the long-term average for 1981-2010, with a new record low set in April for Eurasia. North America’s June snow extent was the third lowest on record.

Snow disappeared three to four weeks earlier than normal in western Russia, Scandinavia, the Canadian sub-Arctic and western Alaska because of below-average accumulation and above-normal spring temperatures.

The eight lowest sea ice extents since 1979 have occurred in the last eight years (2007-2014). There is still much less of the oldest, thickest (greater than 13 feet, or four metres) and most resilient ice than in 1988, when it made up 26% of the ice pack. This year’s figure is 10%.

Extent of melting

As sea ice retreats in summer, sea surface temperature across the Arctic Ocean is increasing. In the Chukchi Sea, it is increasing at 0.5°C per decade.

Melting occurred across almost 40% of the surface of the Greenland ice sheet in summer 2014. For 90% of the summer, the extent of melting was above the long-term average for 1981-2010.

In August 2014, the reflectivity (albedo) of the ice sheet was the lowest recorded since satellite observations began in 2000. When less of the sun’s energy is reflected by ice, melting increases. The total mass of the ice sheet remained essentially unchanged between 2013 and 2014.

Declining sea ice allows more sunlight to reach the upper layers of the ocean, triggering increased photosynthesis and greater production of phytoplankton − the tiny marine plants that form the base of the food chain for fish and marine mammals. − Climate News Network

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Sea urchins refine survival instincts as oceans change

Sea urchins refine survival instincts as oceans change

As climate change adds to the threat of extinction faced by many species, new research shows how sea urchins can adapt to the increasing temperature and levels of acidity in Antarctic waters.

LONDON, 17 December, 2014 − The sea urchins of the Southern Ocean could be safe from the threat of extinction. They may not enjoy global warming and the increasingly acid oceans, but new research indicates that they can adapt to climate change.

Researchers from the British Antarctic Survey and Bangor University in Wales − in what they describe as the largest study of its kind − collected 288 urchins of the species Sterechinus neumayeri from waters off the Antarctic Peninsula, carried them to Cambridge in the UK, and tested them in aquarium tanks over a two-year span, covering two full reproductive cycles.

During this time, they report in the Journal of Animal Ecology, they changed the water chemistry and turned up the temperature. The environment was made less alkaline and the thermometer notched up another 2°C − which are the conditions sea creatures could expect by 2100 if the world goes on burning fossil fuels and pumping greenhouse gases under the notorious business-as-usual scenario.

Intricate network

Research like this matters because it helps scientists to better understand the intricate network of environmental conditions that underwrite life on the planet, and because it provides answers to one of the big questions of climate change: how will it affect the estimated seven million species with whom humans share the planet?

According to the journal Nature, the lowest estimate is that 10 species become extinct every week, and the number could be as high as 690 a week. The uncertainty is an indicator of how little is known about the diversity of life on the planet.

The oceans, in particular, have been hard hit by human action. Other marine survival studies have not been encouraging: ocean acidification promises to be very bad news for corals, and therefore for the rich and diverse communities that depend on coral reefs. It also offers a survival threat to bivalves that exploit ocean chemistry to build protective shells.

Other experiments have shown that it can affect the survival behaviour of fish, and can even affect the lugworms that anglers favour as bait for fish.

But the news from the laboratory aquarium in Cambridge is encouraging. It took the sea urchins six to eight months to acclimatise and adjust to the new acidity levels and temperature − but they survived.

Artificial insemination experiments suggested that the urchins could spawn successfully under the new conditions, but to be sure of this, the researchers need more time. Antarctic invertebrates mature very slowly and sea urchins could live for 40 years or more.

“With predictions of warmer, more acidic waters in the future, this work shows how resilient these animals are to climate change,” said Melody Clark, project leader for the Adaptations and Physiology Group at the British Antarctic Survey.

“It also emphasises the importance of conducting long-term experiments in making accurate predictions. These animals live a long time, and so they do everything really slowly. They take around eight months to get used to new conditions, and two years to produce gonads (sexual organs). If we had stopped this experiment at three or even six months, we would have got very different results.”

Change habitat

Sea urchins cannot easily change their habitat: they must adapt or perish. But four-legged, warm-blooded terrestrial creatures have another option. In another instance of long-term research, scientists have established that small mountain mammals are prepared to move uphill as the climate warms.

Karen Rowe, biodiversity research fellow at Museum Victoria in Melbourne, Australia, and colleagues report in Proceedings of the Royal Society that they looked at records of observations of small mammals, made between 1911 and 1934 at 166 sites in the Californian mountains. Then, between 2003 and 2010, they surveyed the same species in the same locations.

Warmer winters are bad for hibernating mammals such as the chipmunk. Image: Vlad Lazarenko via Wikimedia Commons

Warmer winters are bad for hibernating mammals such as the chipmunk.
Image: Vlad Lazarenko via Wikimedia Commons

Altogether, they looked at 30,000 observations that recorded the foraging and breeding ranges of 34 species of chipmunk, gopher, pika, shrew, deer mouse, woodrat and squirrel at altitudes that varied from sea level to about 4,000 metres.

Moving uphill

Since the first, historic set of systematic measurements, the average temperatures in the region have climbed by 0.6°C, and many mammals have shifted their range accordingly – by moving uphill.

The pattern wasn’t consistent, but the researchers identified a problem for those animals that normally hibernate: warmer winters could be very bad news for creatures adapted to the chillier mountain slopes. And those animals that live at the highest altitudes might soon have nowhere to go.

“While mammals can avoid heat stress by behavioural means (such as shifting daily activity), warming winters lead to increased energy expenditures for hibernators and reduce the snow layer, which acts as insulation for non-hibernators,” they conclude.

“Global climate projections suggest that disappearing climates will be an increasing challenge for predicting future species’ responses.” – Climate News Network

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Climate change’s threat of space centre invasion

Climate change's threat of space centre invasion

Rising sea levels and repeated storm damage to natural coastal defences pose an increasing threat to the famous Cape Canaveral rocket launch site in Florida.

LONDON, 15 December, 2014 − Climate change has begun to make its mark on one of America’s most iconic sites – the Kennedy Space Centre at Cape Canaveral in Florida.

Within a decade, according to geologists, the combination punch of rising sea levels and increasing wave energy could start to affect operations at the site where, more than five decades ago, astronauts were launched towards a landing on the Moon.

Peter Adams and John Jaeger, of the University of Florida, have since 2009 been studying the dunes and the beach at Cape Canaveral that historically screened the launch site from even the worst tropical storms.

These dunes were levelled in 2008 during Tropical Storm Fay, in 2011 during Hurricane Irene, and again in 2012 during Hurricane Sandy.

Washed away

Storm waves repeatedly covered a stretch of railroad track built by the US space agency NASA during the 1960s. The line is no longer used, and part of it has been removed to make room for a protective man-made dune. NASA’s own prediction in 2010 was that the line could be permanently breached by 2016.

Hurricane Sandy, the superstorm  that brought catastrophic flooding to New York and caused damage along almost all the US Atlantic seaboard, washed away a section of Cape Canaveral shoreline so close to a US Air Force launch pad that the surrounding fence was left near collapse.

“When you put immovable infrastructure right next to a dynamic environment, something has to give”

Coastal erosion is an enduring fact of life, but during the 1960s the Cape seemed a secure site for one of the great 20th-century adventures.

The two geologists, working as partners with NASA and the US Geological Survey, began looking at a problem that seemed to have been getting worse since 2004: chronic erosion of a six-mile stretch between the two launch pads used for the Apollo missions and space shuttle launches.

According to Dr Adams, the slow rise in sea levels and the increased energy of the ocean’s storm waves – both symptoms of global warming – are almost certainly to blame. He said: “Is it affecting NASA’s infrastructure? The answer’s yes.”

Although man-made dunes will protect the site for the immediate future, the space agency has already spoken of a “managed retreat”. And Dr Jaeger  said: “When you put immovable infrastructure right next to a dynamic environment, something has to give.”

Evidence of flooding

As a coastal facility, Cape Canaveral is naturally vulnerable to hurricanes, which tend to lose their energy as they hit the coasts. But University of Iowa scientists report in the Bulletin of the American Meteorological Society that they have found evidence of flooding by tropical cyclones as far inland as Iowa, in the Midwest.

Gabriele Villarini, a civil and environmental engineer, found the evidence in 30 years’ worth of discharge records from more than 3,000 US Geological Survey stream measurement stations.

Between 1981 and 2011, the US was hit by more than 100 tropical cyclones or hurricanes that did their worst damage at the coast, but could also be linked with major flooding far inland.

“Our results indicate that flooding from tropical cyclones affects large areas of the US and the Midwest, as far inland as Illinois, Wisconsin and Michigan,” Villarini said. – Climate News Network

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