Climate Change Debate – the Scientific Evidence
The severity and speed of man-made climate change is one of the key factors which will determine the amount of food that can be produced in the future. Most of us desperately wish it wasn’t happening and perhaps that explains why people are quick to believe anything coming from the sceptics. The East Anglia email scandal is an example of something fairly insignificant that is used to feed scepticism in the population, most of whom have not looked closely at the evidence or science.
I have heard people say that they would like to see the arguments explained by experts in an easy to understand way.
It’s great therefore that The Royal Society – as the UK’s national academy of science – has responded to eight key misleading arguments by setting out where the weight of scientific evidence lies.
We at Peak Food will show abbreviated versions of each of these arguments.
MISLEADING ARGUMENT 1
The Earth’s climate is always changing and this is nothing to do with humans. Even before the industrial revolution, when humans began pumping carbon dioxide into the atmosphere on a large scale, the earth experienced warmer periods.
WHAT DOES THE SCIENCE SAY?
The world has experienced warmer or colder periods in the past without any interference from humans. The ice ages are well-known examples of global changes to the climate. There have also been regional changes such as periods known as the ‘Medieval Warm Period’, when less sea ice and larger areas of cultivated land were reported in Iceland.
However, in contrast to these climate phases, the increase of three-quarters of a degree centigrade in average global temperatures over the last century is larger than can be accounted for by natural factors alone.
The Earth’s climate is complex and influenced by many things- particularly changes in the Earth’s orbit in relation to the Sun, which has driven the cycle of ice ages in the past. Volcanic eruptions and variations in the energy being emitted from the Sun have also had an effect. But even taking these factors into account, we cannot explain the temperature rises that we have seen over the last 100 years both on land and in the oceans- for example ,eleven of the last twelve years from 1995, have been the hottest years since records started in 1850.
So what is causing this increase in average global temperature? The natural greenhouse effect keeps the Earth around 30c warmer than it would otherwise be and, without it, the Earth would be extremely cold.
The ability of carbon dioxide and other greenhouse gases to act like a blanket and
trap heat has been understood for nearly 200 years and is regarded as firmly established science.
Any increase in the levels of greenhouse gases in the atmosphere mean that more heat is trapped and global temperatures increase-an effect known as ‘global warming’. We know from looking at gases found trapped in cores of polar ice that the levels of carbon dioxide in the atmosphere are now 35% greater than they have been for at least the last 650,000 years. The increase in global temperature is consistent with what science tells us we should expect when the levels of carbon dioxide and other greenhouse gases in the atmosphere increase in the way that they have.
It is alleged that the increased level of carbon dioxide in the atmosphere is due to emissions from volcanoes, but these account for less than one per cent of the emissions due to human activities.
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[...] at http://www.peakfood.co.uk we have abbreviated three of The Royal Society’s responses to arguments people use to challenge man-made climate [...]