Just 2 degrees, a prescription for disaster according to NASA scientist
December 07, 2011
(NATIONAL) -- Think a planet 2 degrees warmer won't mean much for humans or plant and animal life?
As the planet heats up and the polar ice caps melt, polar bears will have some interesting challenges. CLICK TO ENLARGE
Think again, says James Hansen, director of NASA's Goddard Institute for Space Studies. He says the target set by nations in global warming talks about ways to prevent disaster – 2 degrees – will not prevent the devastating effects of global warming and in fact 2 degrees is indeed a prescription for disaster.
Tuesday at the annual American Geophysical Union (AGU) meeting in San Francisco Hansen said the history of ancient climate changes – the history we know about through scientific investigation that occurred over millions of years – gives the best insight into how humans' greenhouse gas emissions will alter the planet and his research suggests the world’s climate is even more sensitive to greenhouse gas emissions than had been suspected.
Meaning this: "What the paleoclimate record tells us is that the dangerous level of global warming is less than what we thought a few years ago…the target that has been talked about in international negotiations for 2 degrees of warming is actually a prescription for long-term disaster," said Hansen.
He was talking about the goal set by climate negotiators in Copenhagen in 2009 to keep the increase in the average global temperature below 3.6 degrees Fahrenheit (2 degrees Celsius). That cap was put in place as a way to hopefully avoid the most devastating effects of global warming
But Hansen believes otherwise.
And if he’s right? The data suggests humans - and the planet as a whole - are in for an interesting new ride that includes things like increasingly intense storms, wider-ranging wildfires and increasing drought.
The warmer stuff gets, the more bad stuff happens.
While glaciers melt in the Swiss Alps we can expect more intense hurricanes and perhaps hotter, bigger, badder forest fires in the United States.
In just the past few decades in the western states more wildfires have blazed across the countryside, burning larger areas for longer periods of time.
Scientists have correlated the blazes with warmer temperatures and earlier snowmelt.
When spring arrives early and triggers an earlier snowmelt, forest areas become drier and stay so for longer, increasing the chance that they might ignite.
And all over the world temples, ancient settlements and other artifacts still stand from ancient civilizations but the immediate effects of global warming may relegate them all to the same fate: fading away as rising seas and more extreme weather bring the potential to damage such irreplaceable sites.
And in a 2007 a group of leading scientists calculated that a rise of two degrees centigrade in global temperatures – the point considered to be the threshold for catastrophic climate change which will expose millions to drought, hunger and flooding – is now "very unlikely" to be avoided.
That study from the United Nation's Intergovernmental Panel on Climate Change (IPCC) put the inevitability of drastic global warming “in the starkest terms,” as one report put it.
It said that major impacts on parts of the world – in particular Africa, Asian river deltas, low-lying islands and the Arctic – are unavoidable and the focus must be on adapting life to survive the most devastating changes.
Just two years earlier in 2005, another authoritative study predicted there could be as little as 10 years before this "tipping point" for global warming was reached, adding a rise of 0.8 degrees had already been reached with further rises already locked in because of the time lag in the way carbon dioxide – the principal greenhouse gas – is absorbed into the atmosphere.
According to various studies here are the consequences of a 2-degree rise in the global temperature:
Arica: Between 350 and 600 million people will suffer water shortages or increased competition for water. Yields from agriculture could fall by half by 2020 while arid areas will rise by up to 8 per cent. The number of sub-Saharan species at risk of extinction will rise by at least 10 per cent.
Asia: Up to a billion people will suffer water shortages as supplies dwindle with the melting of Himalayan glaciers. Maize and wheat yields will fall by up to 5 per cent in India; rice crops in China will drop by up to 12 per cent. Increased risk of coastal flooding.
Australia/New Zealand: Between 3,000 and 5,000 more heat-related deaths a year. Water supplies will no longer be guaranteed in parts of southern and eastern Australia by 2030. Annual bleaching of the Great Barrier Reef.
Europe: Warmer temperatures will increase wheat yields by up to 25 per cent in the north but water availability will drop in the south by up to a quarter. Heatwaves, forest fires and extreme weather events such as flash floods will be more frequent. New diseases will appear.
Latin America: Up to 77 million people will face water shortages and tropical glaciers will disappear. Tropical forests will become savanna and there will be increased risk of coastal flooding in low-lying areas such as El Salvador and Guyana.
North America: Crop yields will increase by up to 20 per cent due to warmer temperatures but economic damage from extreme weather events such as Hurricane Katrina will continue increasing.
Polar regions: The seasonal thaw of permafrost will increase by 15 per cent and the overall extent of the permafrost will shrink by about 20 per cent. Indigenous communities such as the Inuit face loss of traditional lifestyle.
Small islands: Low-lying islands are particularly vulnerable to rising sea levels with the Maldives already suffering land loss.
Note to readers: the day this story was published we heard from Jackie Wolf Heinl.
She is a Senior Environmental Scientist at Tetra Tech in Pennsylvania. Tetra Tech is a leading provider of environmental consulting, engineering, and technical services worldwide.
Jackie pointed out that our article said “increase” in global warming in North America, when the latest data suggests a “decrease” in North America.
Here is her response:
“Recent studies of crop yields show a decrease with global warming in North America. (The article indicates a decrease) Initially, scientists thought yields would increase, and indeed they did in a lab setting where they elevated CO2 levels over plants.
However, agronomists found different yields in the field. It seems that warmer temperature reduced yields, more so then the offsets of increased CO2. I believe they studied corn.
In addition, it has been found that certain fruits and vegetables do not ripen with warmer night time temperatures.
Seems that they need the colder nights, and since night time temperatures have risen even more than daytime temperatures, this is not surprising. I know for sure my tomatoes have been having a tough time the last few years.”
Our thanks for the correction Jackie.