Chapter Predictions

There is considerable scientific research effort being targeted on the likely consequences of climate change particularly within the scenario that the industrialised nations will continue indefinitely with 'business as usual' (BaU). This BaU scenario assumes some changes and improvements in efficiency in technology. Here are some of the predictions.

• Historic sea levels are well recorded in the Bahamas and Bermuda because these islands have not been subject to tectonic rise and fall. Ancient shorelines show that, at its extreme, sea level was 20 m (70 ft) above the present level during an interglacial period 400 000 years ago. This would occur if all the world's vast ice sheets disintegrated. There is a serious risk of this happening to the West Antarctic and Greenland ice sheets and their loss would mean a 12 m rise in sea level (Geology, vol. 27, p. 375).

• In 2001 Antarctic scientists indicated that sea levels could rise by 6 m (20 ft) within 25 years (Reuters). Ultimately, 'when Antarctica melts it [sea level] will be another 110 metres' (Sir David King, The Guardian, 14 July 2004).

• Many millions of people live below one metre above sea level. For example, Singapore and its reclaimed territories will be at risk if the sea level rises above 20 cm. The Thames barrage is already deemed to be inadequate. Hamburg is 120 kilometres from the sea but could be inundated. The mean high tidal water level has increased between 40 and 50 cm since the 1970s.

• The condition of the Greenland ice cap is another cause for concern. According to one scenario 'warming of less than 3°C - likely in that part of the Arctic within a couple of decades - could start a runaway melting that will eventually raise sea levels worldwide by seven metres' (New Scientist, 'Doomsday Scenario', words attributed to Jonathan Gregory of the Hadley Centre, 22 November 2003). According to a BBC report (28 July 2004) the Greenland ice sheet is melting ten times faster than previously thought. Since May 2004 the ice thickness has reduced by 2-3 m. The same report stated that Alaska is 8°C warmer than 30 years ago.

In the UK rising sea levels threaten 10 000 hectares of mudflats and salt marshes. But the most serious threat is to 50 per cent of England's grade 1 agricultural land which lies below the 5 m contour (Figure 2.1). Salination following storm surges will render this land sterile. The University of East Anglia Environmental Risk Unit predicts that the 1 in 100 year storm and related floods will show a return rate by 2030 for:

Milford Haven

Cardiff

Portland

Newhaven

Colchester

3 yrs

4 yrs

A report from a committee chaired by the UK's Chief Government Scientist, Sir David King, predicts that global warming, coastal erosion and the practice of building on flood plains will increasingly raise the level of risk of loss of life and extensive property damage. The panel of scientists behind the report considered four scenarios. The two worst case scenarios more or less correspond to the IPCC

Newlyn

Land below 5 m AOD

Lowestoft Coastal Erosion

Land between 5 and 10m AOD

Newhaven

Land below 5 m AOD

Land between 5 and 10m AOD

Lowestoft

Colchester flJjiSySheemess

Newhaven

Figure 2.1

Land below 5 metre and 10 metre contours

Business as Usual scenario in which there is unrestricted economic development and hardly any constraints on pollution. The report concludes that the population at risk from coastal erosion and flooding could increase from 1.6 million today to 3.6 million by the 2080s. The cost to the economy could be £27 billion per year (Future Flooding, a report from the Flood and Coastal Defence Project of the Foresight Programme, April 2004) (Figure 2.2).

In an interview with The Guardian (14 July 2004) Sir David King stated: You might think it is not wise, since we are melting ice so fast, to have built our big cities on the edge of the sea where it is now obvious they cannot remain. On current trends, cities like London, New York and New Orleans will be among the first to go. He went on: 'I am sure that climate change is the biggest problem that civilisation has had to face in 5000 years' which gives added weight to his pronouncement in January 2004 that climate change poses a greater threat than international terrorism.

• It was stated earlier that the geological record over 300 million years shows considerable climate swings every 1-2000 years until 8000 years ago, since which time the swings have been much more moderate. The danger is that increasing atmospheric carbon up to treble the pre-industrial level will trigger a return to this pattern. The IPCC Scientific Committee believes that the absolute limit of flooding by 2080 under worst case scenario (from the Office of Science and Technology Foresight Report, Future Flooding, April 2004)

Figure 2.2

Areas in England and Wales at risk of

Worst Case Leishmaniasis

accumulation of atmospheric carbon should be fixed at double the pre-industrial level at around 500 parts per million by volume (ppmv). Even this will have dramatic climate consequences.

• The paleoclimate record shows that generally cooling occurred at a slow rate, but that warming was rapid as stated earlier, for example 12°C in a lifetime.

• Global warming poses a serious threat to health. Pests and pathogens are migrating to temperate latitudes. It is already widely understood that illnesses like vector borne malaria and Leishmaniasis (affecting the liver and spleen) are predicted to spread to northern Europe. The UK Department of Health predicts that, by 2020, seasonal malaria will have a firm foothold in southern Britain, including the deadly plasmodium falciparum strain which kills around one million children a year in Africa (Figure 2.3). The incidence of the fatal disease West Nile fever has increased in warm temperate zones. New York had an outbreak in 1999. The Department also estimated that there will be around 3000 deaths a year from heatstroke - a prediction seriously understated if the summer of 2003 sets the pace of change. Higher temperatures would also increase the incidence of food poisoning by 10 000 (Department of Health review of the effects of climate change on the nation's health, 9 February 2001).

• A warmer atmosphere means greater evaporation with a consequent increase in cloud cover. IPCC scientists consider that the net

Figure 2.3

Predicted spread of seasonal malaria in Britain by 2020

effect will be to increase global warming. Water vapour is a potent greenhouse gas.

• Historically relatively abrupt changes in climate have been triggered by vegetation. For example, average temperature rose by 5°C in 10 years 14 000 years ago. Earlier it was said that the paleoclimate record shows that in the past the explosive growth of vegetation absorbed massive amounts of atmospheric carbon resulting in a severe weakening of the greenhouse effect and a consequent ice age. Nature could still be the deciding factor. The Hadley Centre forecasts that global warming will cause forests to grow faster over the next 50 years, absorbing more than 100 billion tonnes of carbon. However, from about 2050 the increasing warming will kill many of the forests, thus returning 77 gigatonnes (billion) of carbon to the atmosphere. This will bring a high risk of runaway global warming. Already there is evidence of changes in growth patterns in the Amazon rainforest. Taller, faster growing trees are taking over from the slower growing trees of the understorey of the forest. This is attributed to the higher levels of CO2 in the atmosphere. In the short term this could mean a net loss in the carbon fixing capacity of the forest since the understorey trees are slower growing and denser in carbon content. Canopy trees are faster growing and lower in carbon content. In the longer term the latter trees are likely to be more susceptible to die-back through heat and drought (New Scientist, p. 12, 13 March 2004).

• A report from the Calicut University, Kerala, by British, Indian and Nepalese researchers predicts that the great rivers of northern India and Pakistan will flow strongly for about 40 years causing widespread flooding. After this date most of the glaciers will have disappeared creating dire problems for populations reliant on rivers fed by melt ice like the Indus and Ganges. It is estimated that all the glaciers in the central and eastern Himalayas will disappear by 2035. Melting glaciers in the Andes and Rocky Mountains will cause similar problems in the Americas (New Scientist, p. 7, 8 May 2004).

• Another danger is posed by the rapid accumulation of meltwater lakes. Meltwater is held back by the mound of debris marking the earlier extremity of the glacier path. These mounds are unstable and periodically collapse with devastating results. It is predicted that the largest of these lakes in the Sagarmatha National Park in Nepal currently holding 30 million cubic metres of water will break out within five years (New Scientist, p. 18, 5 June 1999). The worldwide melting of glaciers and ice caps will contribute 33 per cent of the predicted sea level rise (IPCC).

• The head of research at Munich Re, the world's largest reinsurance group, predicts that claims within the decade 2040-2050 will have totalled £2000 billion based on the IPCC estimates of the rise in atmospheric carbon. He states: 'There is reason to fear that climatic changes in nearly all regions of the Earth will lead to natural catastrophes of hitherto unknown force and frequency. Some regions will soon become uninsurable' (quoted in The Guardian, 3 February 2001).

• We have to add to these natural events the prediction that there will be a substantial increase in world population, mostly in areas which can least accommodate it. At present the greatest concentrations of population are in coastal regions which will be devastated if sea level rise predictions are fulfilled. The UN Population Division estimates that the world figure will reach 8.9 billion by 2050. The US Census Bureau predicted in March 2004 that the present population of 6.2 billion will rise to 9.2 billion by that date. It then believes that the rate of fertility will fall below the replacement level. Even at present 1.3 billion, or one third, of the total world population live in extreme poverty on less than $1 per day.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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