Global warming close to becoming irreversible: Scientists

The world is close to reaching tipping points that will make it irreversibly hotter, making this decade critical in efforts to contain global warming, scientists warned on Monday.
Scientific estimates differ but the world's temperature looks set to rise by six degrees Celsius by 2100 if greenhouse gas emissions are allowed to rise uncontrollably.
As emissions grow, scientists say the world is close to reaching thresholds beyond which the effects on the global climate will be irreversible, such as the melting of polar ice sheets and loss of rainforests.
"This is the critical decade. If we don't get the curves turned around this decade we will cross those lines," said Will Steffen, executive director of the Australian National University's climate change institute, speaking at a conference in London.
Despite this sense of urgency, a new global climate treaty forcing the world's biggest polluters, such as the United States and China, to curb emissions will only be agreed on by 2015 - to enter into force in 2020.
" We are on the cusp of some big changes," said Steffen. "We can ... cap temperature rise at two degrees, or cross the threshold beyond which the system shifts to a much hotter state."
Tipping Points
For ice sheets - huge refrigerators that slow down the warming of the planet - the tipping point has probably already been passed, Steffen said. The West Antarctic ice sheet has shrunk over the last decade and the Greenland ice sheet has lost around 200 cubic km (48 cubic miles) a year since the 1990s.
Most climate estimates agree the Amazon rainforest will get drier as the planet warms. Mass tree deaths caused by drought have raised fears it is on the verge of a tipping point, when it will stop absorbing emissions and add to them instead.
Around 1.6 billion tonnes of carbon were lost in 2005 from the rainforest and 2.2 billion tonnes in 2010, which has undone about 10 years of carbon sink activity, Steffen said.
One of the most worrying and unknown thresholds is the Siberian permafrost, which stores frozen carbon in the soil away from the atmosphere.
"There is about 1,600 billion tonnes of carbon there - about twice the amount in the atmosphere today - and the northern high latitudes are experiencing the most severe temperature change of any part of the planet," he said.
In a worst case scenario, 30 to 63 billion tonnes of carbon a year could be released by 2040, rising to 232 to 380 billion tonnes by 2100. This compares to around 10 billion tonnes of CO2 released by fossil fuel use each year.
Increased CO2 in the atmosphere has also turned oceans more acidic as they absorb it. In the past 200 years, ocean acidification has happened at a speed not seen for around 60 million years, said Carol Turley at Plymouth Marine Laboratory.
This threatens coral reef development and could lead to the extinction of some species within decades, as well as to an increase in the number of predators.
As leading scientists, policy-makers and environment groups gathered at the "Planet Under Pressure" conference in London, opinions differed on what action to take this decade.
London School of Economics professor Anthony Giddens favours focusing on the fossil fuel industry, seeing as renewables only make up 1% of the global energy mix.
"We have enormous inertia within the world economy and should make much more effort to close down coal-fired power stations," he said.
Oil giant Royal Dutch Shell favours working on technologies leading to negative emissions in the long run, like carbon capture on biomass and in land use, said Jeremy Bentham, the firm's vice president of global business environment.
The conference runs through Thursday.
SOURCE :http://www.moneycontrol.com/news/wire-news/global-warming-close-to-becoming-irreversible-scientists_685437.html

Global warming, spread of infected ticks linked

A new study has documented the rapid growth in Canada of ticks that can cause Lyme disease, and global warming is thought to be a factor.

Ticks capable of carrying Lyme disease went from being almost non-existent in populated areas in Canada in 1990 to now being in 18 per cent of such spots east of Saskatchewan, and this is expected to reach 80 per cent by 2020, says the paper published in the British Ecological Society's Journal of Applied Ecology.

The report did not specifically link global warming with this trend, but lead researcher Patrick Leighton, of the University of Montreal's faculty of veterinary medicine, said rising temperatures are thought to be a reason.

"My opinion is that there probably has been an increase in the spread [of ticks] due to the warming climate," he said.

He added that higher populations of white-tailed deer, which carry the insect, as well as reforestation are also likely facilitating the colonization of ticks in Canada.

The study did show that warmer areas are seeing more rapid growth in ticks. Some of the spots seeing particularly fast growth include southern Quebec, southern and eastern Ontario, and southern Nova Scotia, Leighton said.

He said most areas in Western Canada do not have significant tick populations.

Ticks are typically found in wooded areas.

Asked about how a changing climate is affecting the way Canadians live, Leighton said: "I think it's a reality. The flip side of that is it's making getting into the outdoors in Canada more feasible."

An early sign of Lyme disease, according to the Public Health Agency of Canada, is a circular rash at the site of the tick bite.

Fatigue, chills, fever, head-aches, and muscle and joint pain often follow. If untreated, the disease can lead to nervous system disorders, multiple skin rashes, heart palpitations, extreme fatigue and general weakness, but is rarely fatal, the agency says on its website.

Early treatment with antibiotics is effective in eliminating the illness most of the time, it adds.

Read more: http://www.vancouversun.com/health/Global+warming+spread+infected+ticks+linked/6256364/story.html#ixzz1oLeuX0A0 

Falling clouds may combat rising global warming

Melbourne, Feb 22 (ANI): Falling levels of cloud height across the world, possibly triggered by increasing global temperatures, may have a cooling impact on global warming, a new study has suggested.

 

The first 10 years of data from the NASA Terra satellite, which uses nine cameras at different angles to produce a stereo image of the world's clouds, revealed that their average height has come down by about 1 per cent, or 30 to 40 metres.

 

Most of the reduction was because of fewer clouds occurring at very high altitudes, according to the study by Auckland University scientists.

 

"This is the first time we have been able to accurately measure changes in global cloud height and, while the record is too short to be definitive, it provides just a hint that something quite important might be going on," said lead researcher, Professor Roger Davies.

 

In a "negative feedback mechanism", lower cloud height would allow the Earth to cool to space more efficiently, reducing the surface temperature of the planet and potentially slowing the effects of global warming, the Age reported.

 

"We don't know exactly what causes the cloud heights to lower but it must be due to a change in the circulation patterns that give rise to cloud formation at high altitude," Professor Davies said.

 

The Terra satellite is scheduled to go on with collecting data through the remainder of this decade.

 

"If cloud heights come back up in the next 10 years we would conclude that they are not slowing climate change," Professor Davies said.

 

"But if they keep coming down it will be very significant," Professor Davies added.

 

The study has been published in the journal Geophysical Research Letters. (ANI)

SOURCE:http://www.newstrackindia.com/newsdetails/2012/02/22/269768-Falling-clouds-may-combat-rising-global-warming.html