Читать книгу How Can I Stop Climate Change: What is it and how to help - Литагент HarperCollins USD, F. M. L. Thompson - Страница 65

The complexity of the Earth’s climate means that there has been some scientific uncertainty about global warming. Although the theory of the greenhouse effect was first put forward more than 100 years ago, clear evidence that it was happening was not readily available until the 1970s.

Today there is little room for doubt that climate change is happening and that it is caused by human activity. The IPCC – a naturally cautious body – stated in 2007, ‘Most of the observed increase in global average temperatures since the mid-20th century is very likely (>90 per cent) due to the observed increase in anthropogenic greenhouse gas concentrations.’

But earlier scientific uncertainty has proved a fruitful area for media debate, amplifying the doubts of people who have questioned climate change. Some have exploited scientific doubt to spread complacency and confusion because they have seen addressing climate change as a threat to their interests. Certain companies, for example, have tried to divert attention from the environmental impact of fossil fuels.

“Some will always make a case for doubt in an issue such as this, partly because its implications are so frightening. But what is not in doubt is that the scientific evidence of global warming caused by greenhouse gas emissions is now overwhelming.

Tony Blair, UK Prime Minister (1997-2007)

Scientists have explored alternative theories on the rising temperatures – for example, that they are down to variation in the sun’s cycles. But this does not explain the fit between rising levels of greenhouse gases and rising temperatures. In fact, computer models looking at the effect of the sun’s output on our current climate show that if natural variations were the cause, the Earth should now be cooling, not getting hotter.

The sun’s activity has in fact been decreasing since 1985. Natural phenomena simply do not explain why temperatures have risen in the past 30 years.

An assessment of more than 900 scientific studies on climate change, published over a ten-year period, found that none of the research disputed the consensus view that human activity is responsible for global warming.