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photos.com; Issei Kato/Reuters

TENYEAR TIME LIMIT

The world has ten years in which to

take action on global warming if it’s

to avoid disaster, according to a NASA

climate scientist. Speaking at a climate

change conference in California,

James Hansen said that governments

must control CO 2 emissions if the global

rise in temperature is to be limited to

1°C. If no action is taken, the planet

will warm by 2°–3°C, with disastrous

consequences. “I think we have a very

brief window of opportunity to deal

with climate change… no longer than

a decade, at the most,” he said.

PERMAFROST THAW

Glacier loss accelerating, water shortages on the way

Melting permafrost in Siberia is

producing more of the potent

greenhouse gas methane than

previously thought, according to joint

research by Russian and US scientists

published in the journal Nature.

A recent study led by Dr Georg Kaser, a glaciologist from the University of Innsbruck in Austria, has revealed that the rate at which glaciers are melting has signifi cantly accelerated during the past fi ve years and could lead to water shortages in as little as three decades. Kaser and his team used measurements taken from 300 glaciers in a wide variety of locations since the 1940s to construct a general picture of the state of the world’s land-based ice. They found that between 1940 and 1970, the world’s glaciers and ice caps were consistently growing, but after 1970, the trend reversed, and glaciers began to melt, their decline accelerating during the past fi ve years. Kaser speculated that global dimming – where increased air pollution reduces the amount of sunlight reaching the ground – may have been responsible for the period of growth. He was more defi nitive about the post-1970 decline, stating that “there’s very, very strong evidence that this is down to human-caused changes in the atmosphere”. Meanwhile, a report from 20 leading UK environmental groups has warned that global warming is having a larger impact on glaciers in the Andes than elsewhere. Some are melting so rapidly that they may disappear within 15–25 years, threatening the water supplies of settlements in Colombia, Peru, Chile, Venezuela, Ecuador, Argentina and Bolivia.

Three steps to stabilising carbon emissions The world’s carbon emissions could be reduced by 60 per cent by the year 2050 if governments took just three low-cost steps, according to strategists at fi nancial consultancy PricewaterhouseCoopers (PwC). The ‘green growth plus’ strategy, published in a new PwC report, suggests that by increasing the

use of renewable and nuclear energy, using more effi cient energy sources and widening the use of carbon capture and storage technologies could have a signifi cant eff ect on emissions. The report estimated that shifting to renewable fuels alone would reduce carbon emissions by a quarter, while increasing energy effi ciency would reduce emissions by a third and using carbon capture and storage technologies would lead to a further 20 per cent reduction. This three-step approach wouldn’t aff ect long-term economic growth substantially, according to PwC’s head of macroeconomics, John Hawksworth. “Estimates suggest that the level of gross domestic product might be reduced by no more than two to three per cent in 2050 if this strategy was followed, equivalent to sacrifi cing only around a year of economic growth for the sake of reducing carbon emissions in 2050 by around 60 per cent,” he said.

Although the so-called thaw lakes

were known to produce methane,

the magnitude of the emissions was

uncertain. “Methane fl ux from thaw

lakes in our study region may be

fi ve times greater than previously

estimated,” the scientists wrote.

ICECORE ANALYSIS

A recently extracted Antarctic ice core

has provided further evidence that

carbon emissions have accelerated in

recent years and that the climate of

the future will be dangerously warm.

In-depth analysis of tiny air bubbles

inside a 3.2-kilometre core of ice

has shown that levels of CO 2 in the

atmosphere are higher now than they

have been for 800,000 years and the

fastest increase in CO 2 emissions has

occurred during the past 17 years.

Second-largest ice shelf not melting A group of British Antarctic Survey scientists has used a newly developed technique to demonstrate that the second-largest ice shelf in Antarctica hasn’t yet been aff ected by rising global temperatures. The loss of ice shelves in other parts of the Antarctic has been cited as a key indicator of global warming, but the Filchner-Ronne Ice Shelf – a mass of ice with an area about twice that of Great Britain and a thickness of up to four kilometres located east of the Antarctic Peninsula – appears not to have been aff ected. The scientists employed photo-sensitive radar to send signals down through the ice shelf to its base. The time it took for the signals to rebound was then translated into millimetre-exact distances and revealed the rate at which the bottom of the ice shelf was melting.

The penny drops…

“It was a bloody hot day, 33°C and

a north wind… And a bunch of

people, not just farmers, were

saying: ‘Maybe there is something

in this climate change thing.’”

Australian Foreign Minister

Alexander Downer, October 2006 G

DECEMBER 2006 www.geographical.co.uk 13