Helping climate science make sense.

Record Warm Ocean Waters Aiding Atlantic Hurricanes This Season

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By Andrew Freedman

Sea surface temperature departures from average (anomalies) for the
week of Aug. 22-28, 2010. Credit: IRI.

As we've demonstrated in this slideshow, the Atlantic Ocean is downright sizzling right now, with record-breaking water temperatures in some areas. This makes it more likely that there will be an above average number of hurricanes this season, including more major hurricanes of Category Three strength or above. And – as Hurricane Earl has demonstrated – it also increases the odds that major hurricanes will be able to maintain their intensity in areas they seldom frequent. 

The above map of sea surface temperature anomalies from the last week of August shows the abundance of unusually warm water in the Atlantic, from the coast of Africa to southern New England. This is one of the reasons why the U.S. National Oceanic and Atmospheric Administration (NOAA) has predicted an above average hurricane season, and helps explain how Earl was able to stay so strong as it neared the Carolinas.

According to Weather Underground meteorologist Jeff Masters, Hurricane Earl became the third strongest hurricane to be observed so far to the north in the Atlantic Ocean when it maintained Category Four intensity on its approach to the North Carolina coastline earlier this week (it weakened steadily thereafter due to a combination of factors). On September 2 Masters wrote:

Only Hurricane Esther of 1961 and Hurricane Connie of 1955 made it fa...

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Climate in Context: West Antarctic Melting, Flying Over Hurricane Earl

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By Michael D. Lemonick

Tiny Sea Creatures Shed Light on West Antartic Melting


Bryozoans that can be found on Southern Ocean
Continental Shelves. Credit: British Antarctic Survey.

During the last warm interval between the ice ages – a time, about 130,000-114,000 years ago, known as the Eemian period – the Earth got warmer than it is today, and sea level rose higher. And since we’re currently heading for warmer temperatures again, thanks in large part to human generated greenhouse gases, scientists are looking back at the Eemian for clues about what our own future might look like.

One more clue has just been published, in the journal Global Change Biology. Much of the rise in Eemian sea level – about five meters, or 16 1/2 feet higher than it is today – presumably came from ice melting off Greenland. But some probably came from Antarctica as well, and sea creatures known as bryozoans seem to confirm that idea.

Field researchers from the British Antarctic Survey have shown that colonies of bryozoans on opposite sides of the West Antarctic Sheet are more similar to each other than they are to bryozoans along the nearby coast. This suggests that they were in direct biological communication sometime in the past – suggesting in turn that a seaway once existed in a region that’s now buried under thousands of feet of ice. As the paper’s lead author David Barnes says in a press release on the British Antarctic Survey website: 

“The West Antarctic Ice Sheet...

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Climate in Context: Review Panel Calls for IPCC Fixes; Hurricane Earl Strengthens

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By Michael D. Lemonick and Andrew Freedman

Review of Climate Panel Recommends Organizational Changes, But Reaffirms Scientific Findings

Back in March, United Nations officials decided they had to respond to a series of attacks on the credibility of the Intergovernmental Panel on Climate Change (IPCC), which was founded by the U.N. and World Meteorological Organization in 1988. Among other things, critics asserted that the most recent IPCC assessment report, which was published in 2007, contained errors, and that its authors failed to properly assess uncertainties in projections of future climate. Critics also said the IPCC Chairman, Rajendra K. Pachauri, might be guilty of conflicts of interest (an accusation that evidently didn’t have much substance) and more.

So the U.N. went to a body called the InterAcademy Council, made up of representatives from 18 national science academies in major countries including the U.S., France, the U.K., Germany and China. The Council in turn recruited Harold Shapiro, a Princeton economist and the university’s president emeritus, to run an independent investigation.

That investigation is now complete, the report written and the verdict in. “The Committee found that the IPCC assessment process has been successful overall,” says the Executive Summary. "However the world has changed considerably since the creation of the IPCC, with major advances in climate science, heated controversy on some climate-related issues, and an incre...

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Climate in Context: August 27, 2010

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By Alyson Kenward and Michael D. Lemonick

More on the Sun-Climate Connnection


Graphic of a satellite observing a distant star.
Credit: UCAR/Institute of Astrophysics of the
Canaries.

A brightening Sun has largely been debunked as the reason for rising global temperatures over the past half-century or so. But that doesn’t mean solar changes can’t influence climate. In the first half of the 20th century, in fact, solar brightening may indeed have been a major factor in global warming. Changes in Earth’s orientation to the Sun, meanwhile, are believed to have triggered the start and end of ice ages over the past many hundreds of thousands of years.

More recently, solar physicists have been watching the Sun go through a period of unusual inactivity, with fewer sunspots than normal —which usually goes with an overall Solar dimming. They even thought the Sun might be entering a new version of the Maunder Minimum, when sunspots were depressed for decades, and the world went though an especially cold period that included the Little Ice Age.

It’s not entirely clear what triggered the recent drop in sunspot activity, although solar physicists have some ideas. It’s also unclear whether the even more recent recovery means things are back to normal—but either way, a complete understanding of climate isn’t possible without a good understanding of how the Sun waxes and wanes.

Which is why a new study out of the National Center for Atmospheric Research is poten...

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Climate in Context: August 25, 2010

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By Andrew Freedman

New Study Says Geoengineering Schemes Will Struggle to Reduce Sea-Level Rise

Graphic showing different geoengineering concepts. Credit: Lawrence Livermore National Laboratory.

As we’ve detailed, geoengineering is increasingly being viewed by some scientists, ethicists, and policymakers as an option to seriously consider in order to prevent the most severe consequences of climate change. Various proposals have been put forward, including injecting sulfur dioxide (SO2) into the stratosphere to reflect incoming solar radiation, or launching large space mirrors that would also redirect incoming heat from the sun. Such measures could theoretically cut down on the temperature increase that would otherwise occur due to human emissions of greenhouse gases, such as carbon dioxide.

But could they be effective in preventing sea level rise, one of the most far-reaching and worrisome consequences of climate change?

Not unless you are willing to go all in on geoengineering – while also significantly reducing greenhouse gas emissions – says a new study published by an international team of researchers. The study, published in Proceedings of the National Academy of Sciences, analyzes the effects that five different geoengineering approaches would have on sea level rise, and finds that all but the most aggressive geoengineering proposals would still allow sea level to increase substantially during this century. A key reason for this is that whil...

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