The issue of climate change is a reality and one that is beginning to have destructive consequences. We can make that choice to do something about the changes taking place and therefore must act on behalf of those that cannot do it for themselves and as a result will be lost to us forever.
By studying the instrumental records of a number of climate elements there is proven evidence that indicates a relationship between the man-made enhancement of the natural greenhouse effect through greenhouse gas emissions and the observed global temperature increase during the twentieth century. Combined land and ocean temperatures analyses indicate that during the last decade globally averaged surface temperatures have been higher than in any decade in the past 140 years. Over the whole period, a global temperature rise of about 0.5oC/100 years has been observed.
CLIMATE CHANGE - THE PROBLEM
Prediction of climate change over the next 100 to 150 years is based solely on climate model simulations. The vast majority of modelling has concentrated on the effects of man-made pollution to the atmosphere by greenhouse gases. The main concern is to determine how much the Earth will warm in the future. According to these simulations, global average surface temperatures may rise between 2 and 4oC by 2100 if global development continues at present rates. This rate of climate change is faster than at any time during history, supporting evidence that man-made emissions effect climate change. If nations fail to respond, the world may experience numerous adverse impacts as a result of global warming.
POTENTIAL EFFECTS TO THE UK FLORA
Climate change has potential risks for the UK. Most critical, are the frequency and changes in extreme conditions such as hot, dry summers, drought and storms. It is likely that the occurrence of hot, dry summers will increase, while the chance of extreme cold winters will decrease. Average temperature is expected to increase by 1.5oC by 2050, the equivalent to a decrease in altitude of approximately 200m and a shift southward in latitude of 200-300km.
Higher temperature would reduce the water holding capacity of soils increasing the chance of soil moisture deficits. These changes may have serious effects on the types of crops, trees and other vegetation that soils support. A loss of organic matter would affect the stability of soil structure and ecological habitats nationally. If the water table rose with rising sea levels, a change in soil processes would result. Soils would become more saline and unsuitable for growth of many species.
A sustained rise in mean surface temperature exceeding 1oC, with associated extreme weather events and soil water deficits, would have marked effects on the UK flora and fauna. There may be significant movements of species northwards and to higher elevations. Predicted rates of climate change may be too great for many species to adapt genetically. Many native species and communities would be adversely affected and may even be lost to the UK, especially endangered species. It is possible that there would be an increased invasion and spread of alien weeds, pests, diseases and viruses, some of which may be potentially harmful to other species.
CLIMATE CHANGE - WHAT WE MUST DO
The main objective of the UN Framework Convention on Climate Change is to stabilise greenhouse gas concentrations in the atmosphere at a level that makes climate change slow enough to allow ecosystems to adapt naturally. Current levels of gas emissions will cause a climate change that many species and ecosystems will not be able to adapt to. It is currently believed that most ecosystems can withstand a 0.1oC global temperature change per decade, before experiencing severe ecological stress, leading in some cases to species extinction. The composition and geographical distribution of unmanaged ecosystems will change as individual species respond to new conditions differently.