Information about Global Warming

In the UK we have seen 4 out of 5 of the hottest years ever recorded in the last 10 years. The winter of 2006/7 was the warmest since 1914, with the Midlands region being the warmest since the mid-17th century. Average winter temperatures being on average 2 degrees C above normal. Are these just usual variations or the early signs of global warming?

The main figures involved are that a rise of C0₂in the atmosphere to about 450 ppm (ppm by volume) (or 0.0675% by weight) will result in a 2 degree rise on global temperature, while a rise to 550 ppm will produce about 3^O rise, and to 650 ppm a 4^O rise. 2⁰will bring significant changes in climate,but rises above 2^Omay lead to 'runaway' global warming - where the oceans and soils warm up so much that they release carbon dioxide, which in turn encourages them to warm up some more.

The EU Council of Ministers has an objective of limiting global average temperature increase to no more than 2°C above pre-industrial levels, which it has associated with limiting atmospheric greenhouse concentrations to well below 550ppm carbon dioxide equivalent (CO2e). A 550 ppm CO2e stabilisation goal, means a carbon dioxide concentration of only around 450-500 ppm.

The present world level (Jan 2007) is 383 ppm, which is over100ppm above the pre-industrial average. CO₂ level rises about 2ppm/yr. Fossil fuel emissions are about 7.5GT (Giga Tons) carbon per year which corresponds to about 3.5ppm CO₂ increase per year, with about half absorbed by natural 'sinks'. More on Temperature & History.

According the UK's Scientific Adviser Prof Sir David King: "So if we were sitting here saying we could turn off emissions tomorrow, I would be saying 400-450 ppm. But being realistic, 550 ppm is probably still the right level to be targeting". If this is CO₂ only, it means you have to add another 50ppm or so for methane, nitrous oxides and the other 3 GHGs, that takes it well over 600ppm CO₂e.

A quick 'carbcalc' means that at this rate, global world temperature will rise by two degrees by 2040. 2⁰ will produce droughts in Africa ( so there will be wars between neighbouring countries over boundary water) and excess rain in Middle East producing floods killing millions. And by the end of century we may be in the runaway scenario....

The Intergovernmental Panel on Climate Change (IPCC), consisting of scientists from 40 countries and representations form 113 countries, concludes in its fourth report that global warming is happening, and is very likely (probability is more than 90%) caused by human emissions of 'greenhouse gases' .

Student Guide and Activities (good) on the Greenhouse Effect & Global Climate Change (Dear Reader: Do you know if anybody has 'translated' these, or something like them into UK national curriculum or into some sort of VQs?)

Predicting Global Warming in UK

Global Warming

Environmental Practice at Work Publishing Company Ltd.