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  Yahoo News 9 Aug 07
Global warming will step up after 2009: scientists
By Deborah Zabarenko, Environment Correspondent

Yahoo News 9 Aug 07
Global Warming to Slow Down, Then Speed Up Again
Andrea Thompson LiveScience Staff Writer

National Geographic 9 Aug 07
Warming to Level Off, Then Speed Back Up, New Model Predicts
Mati Milstein

BBC 9 Aug 07
Ten-year climate model unveiled

Scientists say they have developed a model to predict how ocean currents, as well as human activities, will affect temperatures over the next decade.

By including short-term natural events, such as El Nino, a UK team says it is able to offer 10-year projections. Models have previously focused on how the globe will warm over a century.

Writing in Science, Met Office researchers project that at least half of the years between 2009 and 2014 are likely to exceed existing records.

However, the Hadley Centre researchers said that the influence of natural climatic variations were likely to dampen the effects of emissions from human activities between now and 2009.

But over the decade as a whole, they project the global average temperature in 2014 to be 0.3C warmer than 2004. Currently, 1998 is the warmest year on record, when the global mean surface temperature was 14.54C (58.17F).

Doug Smith, a climate scientist at the Hadley Centre, explained how the new model differed from existing ones.

"On a 10-year timescale, both natural internal variability and the global warming signal (human induced climate change) are important; whereas looking out to 2100, only the global warming signal will dominate."

The latest assessment from the Intergovernmental Panel on Climate Change (IPCC), said that human activity was "very likely" causing the world to warm, and predicted the global average temperature were probably going to increase by 1.8-4.0C (3.2-7.2F) by the end of the century.

"It is the same model as used in the latest IPCC report's predictions for the coming century, but the difference is that it starts from the real observed status of the ocean and the atmosphere," Dr Smith, the paper's lead author, explained.

"Greenhouse gases and aerosols are also included, but it is really trying to predict any [natural] variability on top of that.

"We start with the present state of the ocean, and we try to predict how it is going to evolve," he told BBC News.

Better understanding

The model, called the Decadal Climate Prediction System (DePreSys), is based on a well established climate model already used by Hadley Centre scientists.

But in order to offer a projection for the coming decade rather than a century ahead, it also assesses the current state of the oceans and atmosphere. This allows the researchers to predict how natural shifts, such as the El Nino phenomenon in the eastern Pacific and the North Atlantic Oscillation, will affect the global climate system.

They hope this data, when combined with projections of greenhouse gas and aerosol emissions from fossil fuels and volcanic eruptions, will present one of the most detailed outlooks to date.

"One reason why the 10-year projection has not been done before is because the ocean has traditionally had very poor observational coverage," Dr Smith said. "They been very sparse and a little bit "noisy" so they have been difficult to interpret what the real temperatures were over large parts of the ocean."

However, recent improvements in data collection from satellites and in-situ instruments have allowed climatologists to improve their understanding of how ocean dynamics influence the climate system.

He added that decadal outlooks would provide businesses and politicians with meaningful information.

"Nearly all businesses have to make decisions on that sort of timescale; they plan for the next five to ten years. "The climate has already changed, and it is continuing to change; people need the best information available to help them adapt to these changes."

Yahoo News 9 Aug 07
Global Warming to Slow Down, Then Speed Up Again
Andrea Thompson LiveScience Staff Writer

The pace of global warming may slow down over the next few years, before speeding up again, a new study says.

The results of the study, detailed in the Aug. 10 issue of the journal Science, are based on a modified climate model that better predicts potential climate change on shorter time scales, the authors say.

"It's really aimed at the coming 10 years, whereas previous projections are aimed at the coming century or so," said lead researcher Doug Smith of the U.K. Met Office.

Unlike most models, Smith's model predicts changes in the internal variation of Earth's climate (from phenomena such as El Niño), in addition to the outside forcings to the climate from greenhouse gases, aerosols and solar radiation.

Models predicting what could happen by 2100—as most models do, including those used in Intergovernmental Panel on Climate Change (IPCC) estimates—don't need to directly predict internal variability.

While they do still include internal variations in Earth's climate system, the global warming signal tends to overwhelm any effects of natural variability when forecasting out so far.

"By a hundred years' time, the global warming will be much greater than any sort of internal variability," Smith explained. "But in the coming 10 years, the internal variability and global warming could be comparable, especially regionally."

To test whether the modifications improved short-term projections, Smith and his team ran the model from starting points in the 1980s and 1990s and found that the model did "improve the skill of the forecast," Smith told LiveScience.

Decade-scale and more regional projections are important to planners and businesses who are trying to prepare for the effects of climate change.

"There's a lot of people interested in the coming 10 years," Smith said. "We can improve our forecasts on the sort of 10-year period, so we can give information that's likely to be very useful for planners and businesses to adapt to climate change."

The model's projections, which were run starting from June 2005, have been on-track so far, predicting that internal variations will offset some of the globe's overall warming. But that doesn't change the ultimate outcome of global warming, Smith said.

According to the model results, at least half of the years after 2009 will be warmer than 1998, the warmest year on record.

"Climate change is still going to happen, it's still going to warm over the coming century," Smith said. "By the end of the coming 10 years it's still going to have warmed up substantially."

National Geographic 9 Aug 07
Warming to Level Off, Then Speed Back Up, New Model Predicts
Mati Milstein for National Geographic News

Warming due to climate change will level off in the coming years, researchers predict based on a new climate model. But then temperatures will kick back up and continue rising into the early 2010s, producing record highs. In fact, about half of the years after 2009 will be warmer than 1998, the hottest year on record, scientists say.

The new model, created by researchers at the Met Office Hadley Centre in Exeter, is the first to predict such specific fluctuations in global climate. Doug Smith, a scientist at the Met Office and co-author of a paper on the new model, warns that the initial leveling-off should not be seen as countering previous predictions about global temperature increases.

"This doesn't mean that global warming isn't happening. There is no contradiction there," Smith said. "Warming is still predicted and, in fact, we see a signal of that in the coming ten years."

The new model instead produces more accurate short-term forecasts that can be region specific, Smith and colleagues say.

For example, "what's happening this past year with floods in China, Bangladesh, and England—the increased intensity of flooding—could be related to global warming," said Colin Price, an atmospheric scientist with the Porter School of Environmental Studies at Tel Aviv University in Israel.

But Price, who was not involved in the new study, emphasized that right now it is difficult to blame climate change for any individual event. Natural Factors In general, experts agree that Earth's temperature will rise some 2 to 4 degrees Fahrenheit (1.1 to 2.2 degrees Celsius) above pre-industrial levels in the coming century (get global warming fast facts).

But this prediction is a global average spanning decades and doesn't take regional situations into account. That's because previous climate models have traditionally ignored natural variability in favor of global external factors such as human-made greenhouse gases, atmospheric aerosols, and solar radiation.

The Met Office's model, detailed in tomorrow's issue of the journal Science, includes real-time data on the present state of the atmosphere and oceans, Smith said. It also incorporates natural changes in the ocean's circulation and large-scale ocean temperature anomalies like El Niño events—factors that have never before been included in climate change models.

"This is the first time that these two [groups of factors] have been combined to give a serious forecast for the coming decade," Smith said.

The Porter School's Price is among the experts praising the team's new approach. "They are a lot more exact," Price said. "They are talking of specific years, and none of the other models talk of those specifics."

The model can show, for example, how the continued warming trend could produce more extreme weather in certain regions.

"Where you do have rain you'll have more moisture in the atmosphere, so you'll have more rainfall," Price said. "And in areas where you have dry conditions, you'll have more evaporation from plants, so you'll have drought conditions," he added. "We already see it happening in the Mediterranean."

Pinhas Alpert, head of the department of geophysics and planetary sciences at Tel Aviv University, recently returned from a series of meetings with the Met Office discussing the new model.

He said the British team's approach could influence the way other researchers produce climate change predictions. "The running of a climate model can run into two main types of errors: inaccurately defined initial [atmospheric] conditions and the limitations of the model's design itself," Alpert said.

"The method [the Met Office team has] developed is a way to partially overcome these problems," he continued. "They use recent data about atmospheric conditions [that are] considered a very accurate way of representing the initial conditions."

Yahoo News 9 Aug 07
Global warming will step up after 2009: scientists
By Deborah Zabarenko, Environment Correspondent

Global warming is forecast to set in with a vengeance after 2009, with at least half of the five following years expected to be hotter than 1998, the warmest year on record, scientists reported on Thursday.

Climate experts have long predicted a general warming trend over the 21st century spurred by the greenhouse effect, but this new study gets more specific about what is likely to happen in the decade that started in 2005.

To make this kind of prediction, researchers at Britain's Met Office -- which deals with meteorology -- made a computer model that takes into account such natural phenomena as the El Nino pattern in the Pacific Ocean and other fluctuations in ocean circulation and heat content.

A forecast of the next decade is particularly useful, because climate could be dominated over this period by these natural changes, rather than human-caused global warming, study author Douglas Smith said by telephone.

In research published in the journal Science, Smith and his colleagues predicted that the next three or four years would show little warming despite an overall forecast that saw warming over the decade.

"There is ... particular interest in the coming decade, which represents a key planning horizon for infrastructure upgrades, insurance, energy policy and business development," Smith and his co-authors noted.

The real heat will start after 2009, they said. Until then, the natural forces will offset the expected warming caused by human activities, such as the burning of fossil fuels, which releases the greenhouse gas carbon dioxide.

"HINDCASTS" FOR THE FUTURE

"There is ... particular interest in the coming decade, which represents a key planning horizon for infrastructure upgrades, insurance, energy policy and business development," Smith and his co-authors noted.

To check their models, the scientists used a series of "hindcasts" -- forecasts that look back in time -- going back to 1982, and compared what their models predicted with what actually occurred.

Factoring in the natural variability of ocean currents and temperature fluctuations yielded an accurate picture, the researchers found.

This differed from other models which mainly considered human-caused climate change. "Over the 100-year timescale, the main change is going to come from greenhouse gases that will dominate natural variability, but in the coming 10 years the natural internal variability is comparable," Smith said.

In another climate change article in the online journal Science Express, U.S. researchers reported that soot from industry and forest fires had a dramatic impact on the Arctic climate, starting around the time of the Industrial Revolution.

Industrial pollution brought a seven-fold increase in soot -- also known as black carbon -- in Arctic snow during the late 19th and early 20th centuries, scientists at the Desert Research Institute found.

Soot, mostly from burning coal, reduces the reflectivity of snow and ice, letting Earth's surface absorb more solar energy and possibly resulting in earlier snow melts and exposure of much darker underlying soil, rock and sea ice.

This in turn led to warming across much of the Arctic region. At its height from 1906 to 1910, estimated warming from soot on Arctic snow was eight times that of the pre-industrial era, the researchers said.
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