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(回答先: １０年以内に地球気象が破局―英などの新リポートが警告 [ＡＦＰ＝時事] 投稿者 外野 日時 2005 年 1 月 24 日 23:26:44)
Countdown to global catastrophe
Climate change: report warns point of no return may be reached in 10 years, leading to droughts, agricultural failure and water shortages
By Michael McCarthy, Environment Editor
24 January 2005
The global warming danger threshold for the world is clearly marked for the first time in an international report to be published tomorrow - and the bad news is, the world has nearly reached it already.
The countdown to climate-change catastrophe is spelt out by a task force of senior politicians, business leaders and academics from around the world - and it is remarkably brief. In as little as 10 years, or even less, their report indicates, the point of no return with global warming may have been reached.
The report, Meeting The Climate Challenge, is aimed at policymakers in every country, from national leaders down. It has been timed to coincide with Tony Blair's promised efforts to advance climate change policy in 2005 as chairman of both the G8 group of rich countries and the European Union.
And it breaks new ground by putting a figure - for the first time in such a high-level document - on the danger point of global warming, that is, the temperature rise beyond which the world would be irretrievably committed to disastrous changes. These could include widespread agricultural failure, water shortages and major droughts, increased disease, sea-level rise and the death of forests - with the added possibility of abrupt catastrophic events such as "runaway" global warming, the melting of the Greenland ice sheet, or the switching-off of the Gulf Stream.
The report says this point will be two degrees centigrade above the average world temperature prevailing in 1750 before the industrial revolution, when human activities - mainly the production of waste gases such as carbon dioxide (CO2), which retain the sun's heat in the atmosphere - first started to affect the climate. But it points out that global average temperature has already risen by 0.8 degrees since then, with more rises already in the pipeline - so the world has little more than a single degree of temperature latitude before the crucial point is reached.
More ominously still, it assesses the concentration of carbon dioxide in the atmosphere after which the two-degree rise will become inevitable, and says it will be 400 parts per million by volume (ppm) of CO2.
The current level is 379ppm, and rising by more than 2ppm annually - so it is likely that the vital 400ppm threshold will be crossed in just 10 years' time, or even less (although the two-degree temperature rise might take longer to come into effect).
"There is an ecological timebomb ticking away," said Stephen Byers, the former transport secretary, who co-chaired the task force that produced the report with the US Republican senator Olympia Snowe. It was assembled by the Institute for Public Policy Research in the UK, the Centre for American Progress in the US, and The Australia Institute.The group's chief scientific adviser is Dr Rakendra Pachauri, chairman of the UN's Intergovernmental Panel on Climate Change.
The report urges all the G8 countries to agree to generate a quarter of their electricity from renewable sources by 2025, and to double their research spending on low-carbon energy technologies by 2010. It also calls on the G8 to form a climate group with leading developing nations such as India and China, which have big and growing CO2 emissions.
"What this underscores is that it's what we invest in now and in the next 20 years that will deliver a stable climate, not what we do in the middle of the century or later," said Tom Burke, a former government adviser on green issues who now advises business.
The report starkly spells out the likely consequences of exceeding the threshold. "Beyond the 2 degrees C level, the risks to human societies and ecosystems grow significantly," it says.
"It is likely, for example, that average-temperature increases larger than this will entail substantial agricultural losses, greatly increased numbers of people at risk of water shortages, and widespread adverse health impacts. [They] could also imperil a very high proportion of the world's coral reefs and cause irreversible damage to important terrestrial ecosystems, including the Amazon rainforest."
It goes on: "Above the 2 degrees level, the risks of abrupt, accelerated, or runaway climate change also increase. The possibilities include reaching climatic tipping points leading, for example, to the loss of the West Antarctic and Greenland ice sheets (which, between them, could raise sea level more than 10 metres over the space of a few centuries), the shutdown of the thermohaline ocean circulation (and, with it, the Gulf Stream), and the transformation of the planet's forests and soils from a net sink of carbon to a net source of carbon."
23 January 2005
Global warning has already hit the danger point that international attempts to curb it are designed to avoid, according to the world's top climate watchdog.
Dr Rajendra Pachauri, the chairman of the official Intergovernmental Panel on Climate Change (IPCC), told an international conference attended by 114 governments in Mauritius this month that he personally believes that the world has "already reached the level of dangerous concentrations of carbon dioxide in the atmosphere" and called for immediate and "very deep" cuts in the pollution if humanity is to "survive".
His comments rocked the Bush administration - which immediately tried to slap him down - not least because it put him in his post after Exxon, the major oil company most opposed to international action on global warming, complained that his predecessor was too "aggressive" on the issue.
A memorandum from Exxon to the White House in early 2001 specifically asked it to get the previous chairman, Dr Robert Watson, the chief scientist of the World Bank, "replaced at the request of the US". The Bush administration then lobbied other countries in favour of Dr Pachauri - whom the former vice-president Al Gore called the "let's drag our feet" candidate, and got him elected to replace Dr Watson, a British-born naturalised American, who had repeatedly called for urgent action.
But this month, at a conference of Small Island Developing States on the Indian Ocean island, the new chairman, a former head of India's Tata Energy Research Institute, himself issued what top United Nations officials described as a "very courageous" challenge.
He told delegates: "Climate change is for real. We have just a small window of opportunity and it is closing rather rapidly. There is not a moment to lose."
Afterwards he told The Independent on Sunday that widespread dying of coral reefs, and rapid melting of ice in the Arctic, had driven him to the conclusion that the danger point the IPCC had been set up to avoid had already been reached.
Reefs throughout the world are perishing as the seas warm up: as water temperatures rise, they lose their colours and turn a ghostly white. Partly as a result, up to a quarter of the world's corals have been destroyed.
And in November, a multi-year study by 300 scientists concluded that the Arctic was warming twice as fast as the rest of the world and that its ice-cap had shrunk by up to 20 per cent in the past three decades.
The ice is also 40 per cent thinner than it was in the 1970s and is expected to disappear altogether by 2070. And while Dr Pachauri was speaking parts of the Arctic were having a January "heatwave", with temperatures eight to nine degrees centigrade higher than normal.
He also cited alarming measurements, first reported in The Independent on Sunday, showing that levels of carbon dioxide (the main cause of global warming) have leapt abruptly over the past two years, suggesting that climate change may be accelerating out of control.
He added that, because of inertia built into the Earth's natural systems, the world was now only experiencing the result of pollution emitted in the 1960s, and much greater effects would occur as the increased pollution of later decades worked its way through. He concluded: "We are risking the ability of the human race to survive."