Geoscience Reference
In-Depth Information
In
Table 4
, there is a summary of the effects of climate change by the rise in global tem-
perature. Because of the slowness of the political process many scientists and social sci-
entists have started to think about what a 4°C world would be like. Very few of us discuss
the possibilities of a 5°-6°C world, even the IPCC has avoided discussing a world that
hot. It is, however, important for us to have an understanding of what this sort of climate
change would mean to the planet to ensure we never go there. With sustained global tem-
peratures of 5°-6°C above present-day levels, both Greenland and the Western Antarctic
ice sheet will be committed to full melting possibly by the middle to end of the next cen-
tury. If these two ice sheets completely melt, sea level would rise by 13 m. At the mo-
ment, the UK Environment Agency has plans to deal with a 4 m rise in sea level, which
entail a huge barrier across the mouth of the River Thames, stretching from Essex to Kent.
However, a sea-level rise of 13 m would mean the flooding and permanent abandonment
of nearly all lower lying coastal and urban river areas. At the moment, one-third of the
world's population lives within 60 miles (~96 km) of a shoreline and 13 of the world's 20
largest cities are located on a coast. This means billions of people could be displaced lead-
ing to mass migration. Depending on whether Greenland or the Western Antarctic ice
sheet melted first the North Atlantic Ocean circulation could collapse, creating seasonal
extremes for Western Europe, with very cold winters followed by heat waves every sum-
mer. At least three billion people in the world would become water-stressed. Agricultural
production would start to fail, and billions of people would face starvation. Water and
food security would then become issues of conflict between countries, with some experts
predicting 'eco-wars'. Public health systems around the world could collapse, unable to
cope with the demands. And global biodiversity would be devastated. Let's not go there.
