Thursday, December 15, 2011

Warming Raising Sea Level, Says New Climate Change Report

From USA TODAY by Dan Vergano

Ice-age geologic records suggest Earth's climate will warm faster than expected, pushing the global sea level perhaps more than 3 feet higher within this century, a panel of scientists warned Tuesday.

Speaking at the American Geophysical Union annual meeting here, federal and academic scientists said they reviewed ice core measures spanning more than 500,000 years of Ice Ages and subsequent warming periods to warn that ice sheets in the past had quickly melted once temperatures reached tipping points.

"It's like the ice on your windshield suddenly starting to melt all at once," says Eelco Rohling of the United Kingdom's University of Southampton. "The ice takes a little kicking and then it melts."

Sea-level rise has long been a point of contention among climate scientists, who overwhelmingly agree that humanity adding greenhouse gases such as carbon dioxide to the atmosphere has raised global average temperatures about 1.4 degrees Fahrenheit worldwide in the last century, according to a 2010 National Academy of Sciences report.

Exactly how much hotter it will get by 2100 if humanity doubles the amount of atmospheric carbon dioxide — projected to happen by 2060 at present rates by the 2007 Intergovernmental Panel on Climate Change (IPCC) — remains to be seen. Estimates range from roughly 4 to 9 degrees warmer.

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Carbon dioxide concentrations in the air are 39% higher now than pre-industrial levels.

That number grows every year because the greenhouse gas remains for centuries in the sky. Each degree of warming added to the atmosphere by the increase, the panel members warned, raises the risk of more sea-level rise from melting ice sheets on Greenland and Antarctica.

"We cannot double carbon dioxide," said NASA climate scientist James Hansen, who has been a central figure among climate scientists calling for actions to curb greenhouse gas emissions since 1988. "We will be sending the climate back to a state very different from what humanity is used to."

In particular, Hansen and climate scientist Ken Caldeira of Stanford University pointed to an era 55 million years ago when the globe was ice-cap free and temperatures reached heights far above today's.

"The difference was that took millennia to happen. We're doing it on a much shorter time scale," Caldeira said.

The panel of scientists took issue with a recent Science magazine report led by Andreas Schmittner of Oregon State University that looked at pollen and seafloor records of the last Ice Age that was more than 19,000 years ago.

That study concluded that doubling carbon dioxide was very unlikely to increase global average surface temperatures more than 4.7 degrees. "Virtually impossible to go higher," Schmittner said. Rohling says other estimates see it climbing 8.6 degrees or more.

The 2007 IPCC projected less than 2 feet of sea-level rise from warming in this century, partly because the report called such sudden ice sheet melts too hard to project for reliable estimates.

All of the studies of carbon dioxide doubling effects show temperatures increasing, regardless, Caldeira says.

Because carbon dioxide mostly remains in the atmosphere for centuries, the current high level of carbon dioxide means that a millennia from now there will be a sea-level rise of about 80 feet hitting coasts worldwide, "at some point."

Tuesday, December 13, 2011

Tonga and climate change "Our people are on the line, our cultures are going to disappear"

From: Indybay.org  by Takver - Climate IMC

One World TV interviewed Sione Taulo Fulivai from the small Pacific Island state of Tonga on the last day of the UN climate negotiations at COP17 in Durban. Small Island states face rising atmospheric and sea surface temperatures, rising sea levels spoiling freshwater reservoirs and agriculture and threatening to innundate their land, and changing rainfall pattens. They are on the frontline of global warming.

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Tonga is a nation of 100,000 people with a GDP per capita of US$3711. Tonga and Vanuatu are at the top of a UN list of countries most vulnerable to natural disasters in the Pacific.

Sione Taulo Fulivai said:

"For small islands such as Tonga we have limited resources, so when it comes to finding funding for more people to attend these meetings, we can't cover every area in these negotiations. The problem is every area is so significant for us because our existence is pretty much on the line.

When you put that on the table versus the economies of the developed countries it pretty much comes down to your humanity. So, we think okay our existence is on the line, we have to try as much as we can to try and get as much as we can out of this.

So as a small island state we've got everything to lose, and because we are on the front line of this climate change, we don't know how long we are going to last."

Watch the whole One world TV interview on Youtube, December 9, 2011 - Sione Taulo Fulivai (3:21)

The impacts of climate change and sea level rise on Tonga have been studied for twenty years, but there has been little action in the developed world to reduce emissions to mitigate the problem despite the scientific evidence and even legally binding treaties such as the Kyoto Protocol.

According to the Pacific Climate Futures website Tonga can expect to get hotter, but with little change in rainfall. By 2030 temperatures are most likely to be 0.7 degrees celsius warmer under A1B medium emissions scenario. By 2090 temperatures will be 2.0 °C warmer and annual mean rainfall increases of 5% relative to 1981-2000.

Over the next century the following changes are forecast for Tonga:

  • Surface air temperature and sea-surface temperature are projected to continue to increase (very high confidence).
  • Wet season rainfall is projected to increase (moderate confidence).
  • Dry season rainfall is projected to decrease (moderate confidence).
  • Little change is projected in annual mean rainfall (low confidence).
  • The intensity and frequency of days of extreme heat are projected to increase (very high confidence).
  • The intensity and frequency of days of extreme rainfall are projected to increase (high confidence).
  • Little change is projected in the incidence of drought (low confidence).
  • Tropical cyclone numbers are projected to decline in the south-east Pacific Ocean basin (0-40ºS, 170ºE-130ºW) (moderate confidence).
  • Ocean acidification is projected to continue (very high confidence).
  • Mean sea-level rise is projected to continue (very high confidence).

There is an interannual variability in sea levels of about 18 cm (estimated 5-95% range) after removal of the seasonal cycle. According to the Tonga country report:

The sea-level rise near Tonga measured by satellite altimeters since 1993 is over 6 mm per year, larger than the global average of 3.2 ± 0.4 mm per year. This rise is partly linked to a pattern related to climate variability from year to year and decade to decade. A projected rise in sea level of 5-15 cm by 2030, and 20-60cm by 2090. But sea levels may be more as this does not take into account ice sheet disintegration processes which will have a major impact on global sea levels.

There are also signs that some land areas are sinking which will increase the subjective sea leval rise. New software and technology trialled in 2010 found that "The Tonga tidal station shows a 9.21 mm sea-level rise a year, whilst satellite data records indicate a rise of 6.29 mm a year. This has led to the conclusion that the area around the tidal station is sinking at a rate of 2.92 mm per year. Projections generated under a high climate sensitivity scenario and worse case story line for global greenhouse gas emissions (A1F1) show a possible sea-level rise of 952 mm for Tongatapu by the year 2100."

Tonga already experiences extensive coastal inundation and erosion, significant saltwater infiltration which are expected to worsen as sea levels rise. Increasing sea surface temperatures and acidification will impact Reef degradation that will affect the productivity of coastal fisheries and marine ecosystems.

Increasing temperatures will pose a health risk of more frequent epidemics of dengue fever and foodborne diseases. A UN World Health Organisation country profile has assessed (PDF) that "Tonga has been generally slow to recognize and respond to climate change and human health risk."

As a small nation responding to the impacts of climate change is a big deal. Tonga is being proactive. A joint national action plan for climate change adaptation and disaster risk management was approved by Cabinet in Tonga in July 2010. Significant legislation was also passed: the Environment Management Act 2010 which led to the establishment of the Ministry of Environment and Climate Change, the Renewable Energy Amendment Act 2010 and the Tonga Energy Roadmap 2010 - 2020.

Tonga imports all of it's diesel fuel used to run it's electricity generators. It is well on the road to cut it's energy emissions by the use of more renewable energy. Aggressive targets were set in 2008 for 50% of electricity provided through renewable sources by 2012 and the overall cost of electricity should be reduced by 50%.

The first solar power plant is projected to be in operation in July 2012, with funding support by the New Zealand Government. The 1MW photovoltaic Popua Solar Farm on the main island of Tongatapu, located next to the Tonga Power Limited's Popua diesel power station, is expected to reduce the station's annual diesel consumption by approximately 470,000 litres, and to decrease carbon dioxide emissions by over 2,000 tonnes each year. It will supply about 4 percent of the requirements of the main island of Tongatapu according to a Tonga Energy Roadmap media release.

Sources

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