You may want to catch up or your reading and research. Start here at http://www.climatescience.gov/

From that site you can read the following:

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Global Climate Change Impacts in the United States

Once considered a problem mainly for the future, climate change is now upon us. People are at the heart of this problem: we are causing it, and we are being affected by it. The rapid onset of many aspects of climate change highlights the urgency of confronting this challenge without further delay. The choices that we make now will influence current and future emissions of heat-trapping gases, and can help to reduce future warming. Likewise, our decisions on whether and how to adapt to the degree of warming that is already inevitable can help us reduce the impacts of future warming.

1. Human-induced climate change and its impacts are apparent now throughout the United States. Global warming is unequivocal and is due primarily to human-induced emissions of heat-trapping gases and other pollutants. [This actually is technically an error, if their baseline is the Intergovernmental Panel on Climate Change reports from last year. They assert that humans are the dominant warming influence since 1950 with greater than 90 percent confidence, which is different than the certainty here. (UPDATE 7/18: Susan Hassol helpfully pointed out that the IPCC�s �very likely� confidence level is �greater than 90 percent.�)] Observed changes in the United States include temperature increases, sea-level rise, increased heavy downpours, rapidly retreating glaciers, regional droughts, substantial changes in sensitive wildlife, earlier snowmelt, and altered timing and amount of river flows. Impacts of these changes are apparent in many facets of society including health, water, food, energy, and quality of life.

2. Many climatic changes are occurring faster than projected even a few years ago. Global emissions of heat-trapping gases are now increasing even more rapidly than the highest emissions scenario scientists have been analyzing. Arctic sea ice and the large ice sheets on Greenland and parts of Antarctica are melting faster than expected.

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Global warming brings new iceberg threat to Antarctic ecosystem



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A new global warming threat to the fragile marine ecosystems of Antarctica has been identified, with the discovery that an increasing number of icebergs are tearing up the sea floor and destroying any life in their way.

The shallow habitats of species such as giant sea spiders (video), Antarctic worms, sea urchins and corals are facing a growing risk from icebergs, according to research that shows more bergs are floating freely in coastal waters as temperatures rise.

While these near-shore ecosystems have always been pounded by icebergs, crushing the animals and plants that live there, the rate of destruction is increasing as a warmer climate shrinks the winter sea ice that would otherwise lock the bergs in, scientists said. The retreat of coastal glaciers and the collapse of floating ice shelves also mean that more bergs are being shed into the sea, adding to the likelihood of scouring.

The findings, from a team from the British Antarctic Survey (BAS), indicate that the ecological risks of climate change go farther than those posed by rising ocean temperatures.

Iceberg scour is a natural phenomenon, and while it is destructive on a local level it often adds to broader biodiversity by clearing spaces for new life to populate. Scientists, however, are concerned that a substantial increase in the rate of scouring could have unpredictable consequences, creating swaths of shallow water in which organisms with longer life-cycles cannot become established. �The whole balance of the ecosystem could be affected, with consequences that are very difficult to predict,� said Dan Smale, who led the study.

�The focus of research has all been on rising temperatures, but what has been overlooked is that it isn�t just warming of the water that changes the structure of the ecosystem. The distribution of species is likely to be just as important, and that is going to be affected by iceberg scour.�

The research, published in the journal Science, has been dedicated to Kirsty Brown, who died in 2003 while conducting fieldwork at the BAS�s Rothera Research Station on the Antarctic Peninsula. Ms Brown, 28, who drowned when she was attacked by a leopard seal while snorkling, is named posthumously as one of the authors.

The study was conducted over five years at South Cove, on the Antarctic Peninsula, where temperatures are warming more quickly than anywhere else on the planet, by half a degree celsius each decade. This has led to the collapse of part of the Wilkins Ice Shelf in March, and to the loss of seven other floating shelves over the past 30 years.

The BAS team analysed the effects of these trends on iceberg scour by placing grids of small concrete markers on the seabed, at depths of 5, 10 and 15 metres. These were checked by divers for disturbances caused by iceberg strikes.

Dr Smale said that because sea ice was predicted to shrink further under the impact of global warming, iceberg strike rate was expected to increase.

Source: Times Online

Regarding the continued breakup this austral winter. It is surprising to an extent. But the breakup last year was driven not at all by meltwater but by thinning which reduced the stabilizing pressure of pinning points. The evident weakness and existence of substantial surface cracks already in this area led Humbert and Braun to predict continued breakup soon. They were not thinking of the winter, but given that meltwater was not playing a role here, it is not as surprising. It must also be emphasized that there is a common thread here for the breakup of the Wilkins, Petermann Glacier in Greenland and acceleration of other marine terminating outlet glaciers in Greenland. That is preconditioning for collapse via thinning whether due to surface melt, basal melt by seawater or simply reduced flow into the floating section, the thinning leads to less effective pressure restraining glacier movement, this allows it to accelerate, further thin and then collapse. Same story over and over, basal meltwater is not part of this story.

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(CNN) -- Scientists have identified new rifts on an Antarctic ice shelf that could lead to it breaking away from the Antarctic Peninsula, the European Space Agency said.

A satellite image of the Wilkins Ice Shelf, which could break away from the Antarctic Peninsula.

The Wilkins Ice Shelf, a large sheet of floating ice south of South America, is connected to two Antarctic islands by a strip of ice. That ice "bridge" has lost about 2,000 square kilometers (about 772 square miles) this year, the ESA said.



A satellite image captured November 26 shows new rifts on the ice shelf that make it dangerously close to breaking away from the strip of ice -- and the islands to which it's connected, the ESA said.

Scientists first spotted rifts in the ice shelf in late February, and they noticed further deterioration the following week. The period marks the end of the South Pole summer and is the time when such events are most likely, said Ted Scambos, a glaciologist at the National Snow and Ice Data Center at the University of Colorado in Boulder.

Before the new rifts were spotted this week, the last cracks were noticed July 21.

"These new rifts, which have joined previously existing rifts on the ice shelf, threaten to break up the chunk of ice located beneath the 21 July date, which would cause the bridge to lose its stabilization and collapse," said Angelika Humbert, a scientist from Germany's Muenster University who spotted the cracks with Matthias Braun of the University of Bonn.

Wilkins is the size of the state of Connecticut or about half the area of Scotland. It is the largest ice shelf on the Antarctic Peninsula yet to be threatened.

If the ice shelf breaks away from the peninsula, it will not cause a rise in sea level, because it is already floating, scientists say.

Scambos said the ice shelf is not on the path of the increasingly popular tourist ships that travel from South America to Antarctica. But some plants and animals may have to adapt to the collapse.

The ice shelf had been stable for most of the past century before it began retreating in the 1990s.

Several ice shelves -- Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and Jones -- have collapsed in the past three decades, the British Antarctic Survey said.

Scientists say the western Antarctic peninsula -- the piece of the continent that stretches toward South America -- has warmed more than any other place on Earth over the past 50 years, rising by 0.9 degrees Fahrenheit each decade.

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Hill thanks for the update. This ice bridge will break away, as Humbert and Braun predicted last year and Vaughan predicted a decade ago, though not as fast as is happening. I do not see how it can last through the austral summer. Humbert and Braun provided a good explanation of how this is happening and Glasser and Scambos indicated the process for Larsen Ice Shelf which shares an underlying mechanism summarized here. RealClimate-Wilkins

I posted on other forums about GW and the other costs of not going renewable, and it seems that about half of the posters think that GW is just another way to control the masses. Yet I tell them that the icecaps are melting, and they still don't get it. Then I tell them the solution, and the enviro's are against it. I don't think there is any hope unless Obama kick starts the solutions (and stops environmental nimbyism) and China sells electric cars. Here's the solution...

Concentrated Solar thermal Power. Billions of mirrors placed upon some of the worlds deserts reflect light that heats fluid that fills reservoirs that retain that heat for on demand electrical generation. The amount of space used for roads in the US, if used for mirrors (and all the spaces in between mirrors), would power ALL things American even if all things were converted to electric!

Not only would CSP solve the clean energy objective, CSP would help stop the melting of the icecaps, CSP would solve the post oil crises problem that is looming, CSP would solve the economic problems (by creating millions of jobs) and could even help with positive albedo especially after a better clean power source like fusion or advanced geo kicks in (because the mirrors would reflect sunlight back into space instead of into the generator).

I believe that CSP is the only possible solution since it can be mass produced easily and uses yesterday's tech! Only during construction would there be a disturbance to the desert's environment. Billions of post erected mirrors shouldn't cause any major damage, but without them, the Earth will simply get rid of humanity!

Please tell me if there is any way I could be wrong.
Thanks,
Robert Bernal

The continent of Antarctica is warming up in step with the rest of the world, according to a new analysis.

Scientists say data from satellites and weather stations indicate a warming of about 0.6C over the last 50 years.

Writing in the journal Nature, they say the trend is "difficult to explain" without the effect of rising greenhouse gas levels in the atmosphere.


Heat colours the white continent


Meanwhile, scientists in Antarctica say a major ice shelf is about to break away from the continent.

The Wilkins Ice Shelf is said to be "hanging by a thread" from the Antarctic Peninsula, the strip of land pointing from the white continent towards the southern tip of South America.

In isolation

Most of Antarctica's scientific stations are located along the peninsula, and scientists have known for many years that this portion of the continent is getting warmer.

But trends across the bulk of the continent have been much harder to discern, mainly because data from land stations is scarce.

It is somewhat insulated from the rest of the world's weather systems by winds and ocean currents that circulate around the perimeter.


"It's hard to think of any situation where increased greenhouse gases would not lead to warming in Antarctica"
Dr Drew Shindell, Nasa


In the new analysis, a team of US scientists combined data from land stations with satellite readings

"We have at least 25 years of data from satellites, and satellites have the huge advantage that they can see the whole continent," said Eric Steig from the University of Washington in Seattle.

"But the [land] stations have the advantage that they go back much further in time.

"So we combined the two; and what we found, in a nutshell, is that there is warming across the whole continent, it's stronger in winter and spring but it is there in all seasons."

They conclude that the eastern region of the continent, which is larger and colder than the western portion, is warming at 0.1C per decade, and the west at 0.17C per decade - faster than the global average.

The 2007 assessment of the global climate by the Intergovernmental Panel on Climate Change (IPCC) concluded: "It is likely that there has been significant anthropogenic (human-induced) warming over the past 50 years averaged over each continent except Antarctica", with the word "likely" in this context meaning "at least 66% probability".

The scientists said this study did not change that picture, with natural climatic cycles probably involved as well as elevated greenhouse gas concentrations.

"It's hard to think of any situation where increased greenhouse gases would not lead to warming in Antarctica," said Drew Shindell from Nasa's Goddard Institute for Space Studies (Giss) in New York.


How the two halves of the continent are heating up


"We're almost certain that greenhouse gas increases are contributing to this warming, but what's difficult is to attribute this warming and so say how much is down to natural warming and how much down to anthropogenic causes."

Last year, scientists from the UK Met Office used climate models to attribute trends at the poles, and concluded that human emissions of greenhouse gases were largely responsible for the observed warming.

Gareth Marshall from the British Antarctic Survey (BAS), who was not involved in the analysis, commented: "This study shows that, similar to the other six continents, Antarctica has undergone a significant warming over the past 50 years.

"The magnitude of this warming is similar to the rest of the southern hemisphere, where we believe it is likely that human activity has played some role in the temperature increase, and therefore it is also likely that this is the case regarding an Antarctic warming."

Cool analysis

Over the last 30 years, satellites have also shown that sea ice is slowly growing in extent around Antarctica, which some observers say indicates a cooling across the continent or at least in the surrounding seas.

But Walt Meier from the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, which follows ice trends at the poles, said wind patterns were probably the main reason.



"Around Antarctica, the winds play a much bigger role than they do in the Arctic," he said.

"If they're blowing northwards you can grow ice quite quickly and in contrast if they blow southwards the ice can contract quickly, whereas in the Arctic it's much more constrained (by land masses).

"So this positive trend in the Antarctic is certainly not an indication of any cooling trend."

One region that has seen spectacular losses of ice in recent years is the peninsula.

A BAS team currently on site is reporting that the Wilkins shelf, about 15,000 sq km in area, is probably about to break free.

"It really could go at any minute, and I wouldn't be at all surprised if the final cracks started to appear very soon," said BAS's David Vaughan.

Flyover of the Wilkins ice shelf

If it does, it will follow the course of other shelves that have made breakaways in recent years, such as the Larsen B in 2002.

Although spectacular, such events are not necessarily due to man-made climate change.

A much bigger question is whether the new analysis of Antarctic warming heralds any major melting in the West Antarctic ice sheet, which could lead to big changes in sea level and global impacts.

"The vulnerability is higher than we thought, but still we face uncertainties in understanding these processes that make it very difficult to forecast when these changes would occur," said Drew Shindell.

Source: BBC