International Issues

The UK Prime Minister has said that climate change is ‘Probably, long term the single most important issue we face as a global community’.

Over the last 100 years, average global temperatures have increased by between 0.4 and 0.8 oC, and are set to increase further. In fact, the 10 hottest years on record have all been recorded since 1990. However, climate change is not simply a case of us all enjoying a bit of warmer weather. Rainfall may become more sporadic, increasing in winter, yet decreasing in summer. The frequency of so-called ‘extreme weather events’ such as droughts, floods, avalanches and storms will increase, consequently meaning that the Earth’s climate will become more unpredictable.

Global warming also causes an increase in sea levels resulting from ocean expansion and the melting of land based ice caps. The British Antarctic Survey estimates that over the past 5 years, on average, glaciers are retreating by 50 metres a year. This is faster than at any time in the past 50 years.

The impacts of climate change could be felt hardest in the poorest countries that have the least responsibility for impacting on the climate, and are least able to deal with the consequences.

Effects of climate change could include:

Agriculture

• A decrease in crop production in tropical and sub-tropical regions leading to famine.
• In the UK, higher temperatures would decrease the yield of cereal crops, and increase the yields of crops such as potatoes, sugar beet and forest trees.
• Agricultural pests that are currently limited by temperature could become more prevalent in the future.

Soils

• Higher temperatures resulting from climate change would reduce the water holding capacity of soils, increasing the likelihood of soil moisture deficits.
• There would be a change in the types of crops that soils can support.
• Soils affected by rising sea levels would become saline and unsuitable for growing crops.
• A change in the structure and stability of soils could reduce the stability of building foundations.

Flora, Fauna and Landscape

• Changes in climate may result in significant movements of species to ‘keep up’ with spatially shifting climatic boundaries. Those species unable to migrate will become increasingly threatened.
• A group of distinguished scientists has predicted that climate change will threaten extinction for a quarter of all land animals and plants by 2050, as climatic changes will result in changes in habitats, and the disruption of complex food webs,
• It is likely there will be an increased invasion and spread of alien weeds, pests, diseases and viruses some of which may be harmful.
• Increased numbers of foreign species of invertebrates, birds and mammals may out-compete native species.

Coastal regions

• The mean sea level has already risen by between 10-25cm during the past century. According to a number of studies, the sea has been rising at the rate of 1-2mm per year over the last 100 years.

• The sea level around the British coastline is expected to rise by between 12 and 67cm by the 2050’s, therefore a number of low-lying areas are vulnerable.
• Flooding would result in damage to structures, agricultural land, rail and road systems.
• A rise in the water table associated with higher sea levels may increase the salinity of groundwater, with consequent effects for water supplies.

Water resources

• Rainfall variability could lead to more droughts.
• Increased temperatures would lead to more demand for water, and irrigation for agriculture, putting pressure on water reserves.

Health

• Extremes of weather result in increased death, illness and injury. In the short-term these can be caused by dramatic events such as flooding, hurricanes and temperature extremes.

• There will be an increase in heat stress mortality, this was already seen in Europe in the summer of 2003 where extreme temperatures killed an estimated 25,000 people.
• Changes in climate will result in a wider geographical area being climatically suited to vectors that spread disease. An example of which is the spread of West Nile Virus carrying mosquitoes.