In regard to the animal world, there are entire branches of the animal kingdom, such as reptiles and insects that thrive with higher temperatures. The fossil record shows the existence of large tropical reptiles that required temperatures in excess of 5 degrees cent. more than todays levels. Tropical forests are robust and adaptable systems over a quite wide range of mean planetary temperatures. It is believed that dinosaurs lived with atmospheric C02 concentrations of 1000 per million (i.e. more than double todays level of 380ppm.) The ecological systems of the planet are thus highly adaptive and there is no optimum temperature for the planet. Some habitats will thrive whilst others will suffer as a result of temperature change. It is simply not a scientifically meaningful question to ask if temperature increase is good for the planet. Aside from factors such as human destruction of forest habitats, temperature increase per se has a number of generally beneficial effects on plant life. Higher temperature causes increased evaporation and rainfall, which is beneficial for plants. Temperature increase also raises the tree line. In the equatorial zones, such as the Bolivian Andes and the Himalayas, the tree line is almost 5000 m, whereas in northern Scandinavia it is 1000 m. approx.(See http://en.wikipedia.org/wiki/Treeline) Thus temperature increase enlarges the envelope in which plant life is viable. Incidentally, CO2 in small quantities is beneficial for plants and enhances plant growth. It is a sort of air borne fertiliser or plant food. It is also possible that temperature increase would enhance agricultural productivity on certain upland habitats. These are the main ecological advantages of planetary temperature increase. The climatic effects of temperature increase can be summarised as a series of shifts in the main climatic zones. Globally there are a number of distinct climatic zones. These are attractively illustrated at http://en.wikipedia.org/wiki/File:MeanMonthlyP.gif This interactive map shows the seasonal oscillation of weather around the equatorial zone. The highest levels of heat and rainfall are concentrated in the tropical/equatorial zones. The map shows the effect of planetary rotation on habitats, due to the Coriolis effect. Tropical/monsoon rain patterns lie on a sort of S.W. to N.E. axis as does the band of desert areas running from the south western Sahara to the Gobi deserts. In terms of a schematic summary the other main zones or global habitats are: desert, polar/tundra, savannah/Mediterranean and temperate/agricultural. Temperature increase is liable to have the following broad consequences on these habitats: Tropical/equatorial zone: intensification Savannah: diminution Desert: intensification. Temperate/agricultural: intensification. Polar/tundra: diminution. [The current debate relates to mean temperature and does not necessarily imply a change in maximum and minimum temperatures (e.g. lowest polar and highest desert temperatures).] In human terms it is notable that there will be large agricultural gains in areas such as Russia, Canada and Scandinavia. Climatic conditions in the United Kingdom are benign across the entire range of temperatures currently under political consideration. Intensification of desert areas is a process that has been going on since the end of the Ice Age. It is very notable in western China and the Gobi desert. In fact, trade routes over the Silk Road were known to have shifted northward before the time of Marco Polo as a result of desertification. Global temperatures have been increasing since the end of the Ice Ages. In general terms an Ice Age will have a dry climate with low sea levels because most of the planets fresh water is frozen in ice sheets. Strictly speaking the increase in sea levels since the Ice Age is a non-climatic phenomenon. Sea level increase is the only possible danger facing the U.K. There is no significant sign of it at present. By contrast, a warm period is associated with rainfall, evaporation, higher cloud levels and higher sea levels. Thus there is a correlation between moisture and warmth that is particularly strong in the equatorial regions. Moderate global warming , in aggregate, is therefore likely to be beneficial for life forms, in particular plant life.