【分析解答题】

The year 2005 was an exceptionally dry one for theAmazon rainforest. Thousands of square kilometers of rainforest were destroyeD、The level of the mightyAmazon river and its tributaries fell to the lowest levels since records began. Fish perished in the abnormally warm waters.Boats were groundeD、Locals were forced to abandon their homes. It was the kind of drought that researchers would expect no more than once a century.

But then came the drought of 2010.As a new research paper published in the journal Science today reveals, last year’s drought was even more severe than 2005. SoBrazil has experienced two "once in a century" climatic events in a decade. Unsurprisingly, scientists are beginning to suspect that something is amiss.
A、link between these crippling droughts and climate change cannot be proveD、But increasingly common drought is consistent with what scientific models predict for a globally warmer worlD、IncreasingAtlantic sea surface temperatures are expected to lead to lower rainfall inBrazil’s great forest.
There is another deeply worrying trenD、 The amount of carbon dioxide pumped into the atmosphere by our societies has fallen in recent years because of the global economic downturn.But the latest readings suggest thatCO₂ ievels in atmosphere still increased over that time. The fear is that this is being driven by a "feedback loop", whereby the impact of climate change itself accelerates climate change. In this case, as the climate heats up, rainforest trees fall and burn, releasing the carbon locked up in them.And this, in turn, accelerates warming further.
Again, the existence of a feedback loop is difficult to prove.But it fits predictions. Normally, rainforests function like great carbon sinks, absorbing a large proportion of theCO₂ that human activity produces.But in 2005, thanks to deforestation, theAmazon became a net emitter of carbon dioxide. In that year, the rainforest is estimated to have emitted some 5 billion tonnes ofCO₂, almost as much as the entire output of the United States.
The pace of deforestation in theBrazilian rainforest appears to have slowed somewhat in recent years.But pressure on rainforests continues in equatorial regions elsewhere, fromCongo to Indonesi
A、We need to preserve the world’s existing arboreal lungs if we are to have any chance of avoiding runaway climate change.But human activity is still depleting this crucial natural asset, even as its role in climatic regulation shows ominous signs of breaking down.
The only viable strategy for preserving the world’s rainforests that has been put forward is ReducingEmissions fromDeforestation and ForestDegradation (REDD、. This scheme would transfer money from high-income countries to developing countries, in order to dissuade them from cutting down their trees for profit.
But to work, this will require an overarching global climate-change treaty, with mandatory emission limits for each country. Without such a framework fiscal transfers between high-income and developing countries witl never be substantial enough to affect behaviour in poor nations and the deforestation, by ranchers and loggers, will continue.Despite the great hopes, the United Nations climate change summit inCopenhagen in 2009 failed to deliver a binding global treaty. Last year’s follow-up summit inCancun was hailed by some environmentalists as a small step forwarD、
But the hour is too late for small steps. The world needs massive action, beginning immediately, to reverse the existing trends on emissions and deforestation. We also need to pray that it is not already too late.
1.What are the two "once in a century" climatic events What do they tell us