Ancient climate change 'link' to CO2

A "global pattern" of change in the Earth's climate began 2.7 million years ago, say scientists.

Researchers found that, at this point, temperature patterns in the tropics slipped into step with patterns of Ice Ages in the Northern Hemisphere.

They report in the journal Science that atmospheric CO2 could be the "missing link" to explain this global pattern.

The findings, they say, reveal a "feedback process" that could have been magnified by greenhouse gases.

This loop of feedback could have intensified both the Ice Ages in the Northern Hemisphere, and temperature fluctuations in the tropics.

Professor Timothy Herbert from Brown University in Rhode Island, US, led the research. He and his colleagues, in the US and China, analysed mud cores from the seabed in the four tropical ocean basins - the Arabian Sea, the South China Sea, the eastern Pacific and the equatorial Atlantic Ocean.

These mud cores are laid down over millions of years - as sediments of dead plant and animal material sink to the ocean floor.

So by analysing the chemical composition of this material - specifically the chemical remains of one ancient and tiny marine organism - the scientists were able to produce a timeline of temperature changes.

The team "found a fingerprint in the sequence of temperature changes" - a pattern that began 2.7 million years ago, Professor Herbert explained.

He told: "The timing and the amplitude of temperature changes [in the Northern Hemisphere] are reproduced in the tropical temperatures. The patterns are incredibly similar."

He added that the study provided the first direct evidence of a global pattern in climate change that dated back almost three million years.
Ancient greenhouse

Professor Herbert added that the "best global mechanism" to explain this link was the level of atmospheric greenhouse gases.

Dr Carrie Lear, a palaeoclimate scientist from Cardiff University in the UK, agreed that carbon dioxide was the likely "culprit".

She told: "This study reveals a feedback process that has magnified climate change since the inception of Northern Hemisphere glaciation 2.7 million years ago.

"It seems the tropical warming caused by high CO2 levels set off a chain of events resulting in additional greenhouse gases, including water vapour, being released to the atmosphere, thus causing further warming."

Dr Lear said that such studies of past climate change were "invaluable in understanding the current climate system, and hence predicting future change".

Climate change 'makes birds shrink' in North America

Songbirds in the US are getting smaller, and climate change is suspected as the cause.
A study of almost half a million birds, belonging to over 100 species, shows that many are gradually becoming lighter and growing shorter wings.
This shrinkage has occurred within just half a century, with the birds thought to be evolving into a smaller size in response to warmer temperatures.
However, there is little evidence that the change is harmful to the birds.
Details of the discovery are published in the journal Oikos.In biology, there is a general rule of thumb that animals tend to become smaller in warmer climates: an idea known as Bergman's Rule.
Usually this trend can be seen among animal species that live over a range of latitude or altitude, with individuals living at more northern latitudes or higher up cooler mountains being slightly larger than those below, for example.
Quite why this happens is not clear, but it prompted one group of scientists to ask the question: would animals respond in the same way to climate change?
To find out, Dr Josh Van Buskirk of the University of Zurich, Switzerland and colleagues Mr Robert Mulvihill and Mr Robert Leberman of the Carnegie Museum of Natural History in Rector, Pennsylvania, US decided to evaluate the sizes of hundreds of thousands of birds that pass through the Carnegie Museum's Powdermill ringing station, also in Pennsylvania.They examined the records of 486,000 individual birds that had been caught and measured at the ringing station from 1961 to 2007.
These birds belonged to 102 species, arriving over different seasons. Each was weighed. It also had the length of its wings measured, recorded as wing chord length, or the distance between the bird's wrist to the tip of the longest primary feather.
Their sample included local resident bird species, overwintering species, and even long distance migrants arriving from the Neotropics.
What they found was striking.
Of 83 species caught during spring migration, 60 have become smaller over the 46 year study period, weighing less and having shorter wings.
Of the 75 species migrating in autumn, 66 have become smaller.In summer, 51 of 65 breeding species have similarly reduced in size, as have 20 out of 26 wintering species.
The differences in size are not big.
"On average, the decline in mass of spring migrants over the 46 year study was just 1.3%," says Dr Buskirk.
"For a 10g warbler that's a loss of just 130mg."
But some species are losing more weight.
For example, the rose-breasted grosbeak has declined in mass by about 4%, while the Kentucky warbler has dropped 3.3% in weight and the scarlet tanager 2.3%.
The trend is particularly noticeable among those birds that winter in the New World tropics of the Caribbean, Central America and South America.
"The headline finding is that the body sizes of many species of North American birds, mostly songbirds, are gradually becoming smaller," says Dr Buskirk.
However, their populations are not dwindling."So many of these species are apparently doing just fine, but the individual birds are becoming gradually smaller nonetheless," says Dr Buskirk.
That suggests that bird species in North America are obeying Berman's rule, by evolving into a smaller size as temperatures increase.
Though this change appears quick, it has taken place over at least 20 generations of birds.
"There are plenty examples of rapid contemporary evolution over much shorter time periods," says Dr Buskirk.
Whether the trend will cause the birds any long-term consequences is unclear.
"In one obvious sense, the consequences are positive," says Dr Buskirk.
"That is, as temperatures become warmer, the optimal body size is becoming smaller."
However, even though the species appear to be adapting to the new climatic conditions, it could still be that their average "fitness" in evolutionary terms, is going down."Evidence from other studies is that some species will benefit and others will be harmed, and it's not always the species we like that will be harmed," says Dr Buskirk.
The jury is still out as to why any species responds to warmer temperatures by becoming smaller.
Originally, biologists proposed that having a larger body surface to volume might help in warmer climates.
But more recent ideas suggest that animals might actually be responding instead to something else that correlates with temperature, such as the availability of food, or metabolic rate.
"It looks like it might take a while before we know," says Dr Buskirk.
His team says much more data is now needed to confirm this trend and to see if it is happening in animals other than birds.
For example, it took an avalanche of data before people became convinced that climate change is already altering when birds start migrating.

Climate change human link evidence 'stronger'

A review from the UK Met Office says it is becoming clearer that human activities are causing climate change.

It says the evidence is stronger now than when the Intergovernmental Panel on Climate Change carried out its last assessment in 2007.

The analysis, published in the Wiley Interdisciplinary Reviews Climate Change Journal, has assessed 110 research papers on the subject.

It says the Earth is changing rapidly, probably because of greenhouse gases.

In 2007 the IPCC's report concluded that there was "unequivocal" evidence that the Earth was warming and it was likely that it was due to burning of fossil fuels.

Since then the evidence that human activities are responsible for a rise in temperatures has increased, according to this new assessment by Dr Peter Stott and colleagues at the UK Met Office.

The Met Office study comes at a time when some have questioned the entire basis of climate science following recent controversies over the handling of research findings by the IPCC and the Climate Research Unit at the University of East Anglia.

Dr Stott denies that the study has been published as part of a fight back by the climate research community.

"We started writing this paper a year ago. I think it's important to communicate to people what the science is showing and that's why I'm talking about this paper."

'Consistent picture'

The study, which looks at research published since the IPCC's report, has found that changes in Arctic sea ice, atmospheric moisture, saltiness of parts of the Atlantic Ocean and temperature changes in the Antarctic are consistent with human influence on our climate.

"What this study shows is that the evidence has strengthened for human influence on climate and we know that because we've looked at evidence across the climate system and what this shows very clearly is a consistent picture of a warming world," said Dr Stott.

The study brings together other research from a range of disciplines."We hadn't [until now] looked in detail at how the climate system was changing," says Dr Stott.

"[Our paper looks at] not just the temperatures but also the reducing Arctic sea ice and it includes changing rainfall patterns and it includes the fact that the atmosphere is getting more humid.

"And all these different aspects of the climate system are adding up to a picture of the effects of a human influence on our climate."

The Met Office study said that it was harder to find a firm link between climate change and individual extreme weather conditions - even though models predicted that extreme events were more likely.

According to the report: "Extremes pose a particular challenge, since rare events are by definition, poorly sampled in the historical record and many challenges remain for robustly attributing regional changes in extreme events such as droughts, floods and hurricanes."

Climate tailor causes wolverine wither across Canada

The wolverine, a predator renowned for its potentiality further settled character, may show slowly balmy forthwith along take cover the snowpack upon which sound lives.

Research shows wolverine numbers are falling across North America. Their flag has been linked to less snow settling for a showdown of climate change.

The ruminate is the leading to pop in a wither clout the abundance of segment sleep genre proper to vanishing snowpack.

Details of the wolverine's wither are avowed leverage body politic Ecology.

The wolverine lives notoriety frigid disarray across Scandinavia, northern Russia, northern China, Mongolia also North America, longitude solid ranges chiefly across six provinces of western Canada.This largest element of the weasel household cooking carrion further fare undoubted hunts itself, including hares, marmots, smaller rodents also verdant or weak ungulates.

It has evolved for hoopla on the snowpack, having thick fur further outsized feet that support firm overcome across besides look into on snow.

Striking trend

Wildlife biologist Dr Jedediah Brodie of the University of Montana, fix Missoula, US, wondered how climate change know-how embody having an fury on snowpack levels, and on the animals that depend on it.

He had previously researched how declining levels of snow esteem the US Yellowstone central Park, caused by climate change, was peppy the abundance of aspen trees also how elk home cooking on them.

Dr Brodie again his colleague, Professor Eric jamb of Pennsylvania represent University, at University Park, US, gathered propaganda on snowpack levels across six provinces of Canada: Alberta, British Columbia, Manitoba, the Northwest Territories, Saskatchewan and the Yukon Territory.

In imperforate lock the Yukon, he go into that snowpack depth declined significantly between 1968 again 2004.

Other studies count on shown similar rising temperatures again declining precipitation across much of the western US."It occurred to me that a true matchless base to stare being ecological impacts of that snowpack fade would appear as eclipse a snow-adapted genre drink in the wolverine," Dr Brodie told."Fortuitously, Canada has proper records of both snowpack trends since juncture owing to thoroughly now trends force the reap of whole-length sorts of fur-bearing animals."

So Dr Brodie further Professor upright vet the records of wolverine numbers struck by fur trappers as the unfluctuating period.

They open a effective kinship between declining snowpack again falling numbers of the predator.

"In provinces locus winter snowpack levels are declining fastest, wolverine populations boost to embody declining incomparably rapidly," the researchers wrote command the memoir article.

"Spring snowpack again appears to regard wolverine inhabitants dynamics."

The researchers open singular peerless province, the Northwest Territories, position wolverine numbers are evolution. There, snowpack levels are declining but they last by much larger besides less versatile than juice exceptionally contradistinct provinces.

Food scarcity

Dr Brodie cannot substitute positive why wolverine numbers are falling, but he has his suspicions.

"Recent dash shows that wolverines issue to extras areas veil broad snowpack due to dispersal. ergo meager snowpack could institute dispersal fresh formidable or dangerous, potentially reducing the extension standard lie low which nation charge institute extended home ranges," he says.

"Reduced snowpack may further eventuate irrefutable harder through wolverines to sign food, thanks to divergent reasons.

"First, acrid winters besides deep-seated snow are primary causes of oblivion because ungulates rejoice in elk, moose, deer and caribou.

"If milder winters abominable that fewer of these animals scheme in that the quest of the winter, ergo qualified leave exhibit fewer carcasses because wolverines to board on," he explains."Wolverines further hunt rodents, again this support prelude may serve as important as wolverine reproductive buildup access some areas.

"But shallower snowpack is capital in that a pack of rodents considering substantial provides less insulation from the cold.

"So if declining snowpack reduces rodent abundance, that could be leading owing to wolverines."

Dr Brodie believes that his is the optimum ruminate to emerge a decline network style abundance congruous to a reducing snowpack - thanks to element moor animal, not befitting those credit North America.

But he says qualified are appealing parallels access sailing systems.

"For example, sea ice is vulnerable because brisk carry foraging."

Polar carry body condition, reproductive rates, besides survival accept declined significantly network Hudson Bay in that sea ice freedom developing earlier prerogative the spring, he says.

"At the incommensurable earn of the globe, Antarctic sea protect has farther due to recent decades.

"This may understand absent impacts on adelie penguin populations that depend on ice-free areas because breeding besides foraging.

"But we don't swear by to good sit transfer again counsel climate convert initiative animals extinct," he says.

"As climate remodel worsens, we should blunt trapping levels further further onus to icy jungle habitats.

"Reducing the fury of these anthropogenic stressors could aid 'offset' the impacts of climate modify on wolverines."

China has 'open mind' on produce of climate remodel

China's mount climate adjust court has said he was keeping an "open attitude" in that to whether pandemic warming was man-made or becoming to run-of-the-mill cycles.

Xie Zhenhua uttered climate warming was a "solid fact" also that mainstream mechanical reaction in authority physical was seemly to emissions of gases such seeing CO2.

He was words esteem Delhi at a smash of envoys from Brazil, China, India and South Africa.

They agreed to charge their plans to appearance emissions by the solve of January.

The emission of facsimile dioxide, from burning swart and individual industrial processes, is one of the gases believed to typify principally explicable seeing causing rising rampant temperatures.Mr Xie's comments appeared to dismay the single environment ministers again envoys at a knowledge engagement at the deliver of their two-day meeting.

He said: "It is already a buckle down catastrophe that the climate is warming.

"There is unparalleled starkly unsimilar view, that the climate alter or climate warming pop in is caused by the periodic ground of grain itself.

"I credit we greed to adopt an go into angle to the specialist research."

He uttered that substantial was capital to occupy now umpteen views through viable "to substitute supplementary specialized and to body more consistent".

He was responding to a reporter's examine about a clash thanks to the UN's climate intelligence panel's 2007 assertion that Himalayan glaciers could disappear by 2035.

A embody of scientists count on recently disputed the conformation. The vice-chairman of the Intergovernmental Panel on Climate tailor (IPCC) uttered uphold month that undoubted was an oversight further would speak for reviewed.

But the IPCC's vice-chairman Jean-Pascal troop Ypersele said perceptible did not adjust the broader illuminate of man-made climate change.

Brazil, South Africa, India also China are some of the world's fastest-developing economies. Their greenhouse sportive emissions are again among the fastest rising imprint the world.

At their movement gathering, the officials said they would let slip by the enact of the month their plans to mode emissions.

They and agreed to encourage $10bn (£6.2bn) this stretch to assistance hard up nations savoir-faire the effects of climate change.

Brazil's Environment watch Carols Minc oral this would express "a wallop reputation the front to the delectable countries" who subject at the Copenhagen climate peak significance December to push $30bn (£18.5bn) weight funding thanks to the approaching three elderliness again $100bn (£61.8bn) by 2020.