Earthwatch's response to climate change
What is Climate Change?
Climate Change or Global Warming is the process by which changes in the concentrations of atmospheric gases result in the retention of heat that would otherwise be radiated back into space.
In the words of the Joint Science Academies' statement (PDF link) issued to G8 leaders "There will always be uncertainty in understanding a system as complex as the world's climate. However there is now strong evidence that significant global warming is occurring." "It is likely that most of the warming in recent decades can be attributed to human activities." "This warming has already led to changes in the Earth's climate.... climate change is real".
What are Greenhouse Gases?
The most mentioned greenhouse gas (GHG) is CO2. However there are several more. Methane, ozone, water vapour, nitrous oxide, sulphur hexafluoride, hydroflourocarbons, perfloroucarbons and chloroflourocarbons all absorb infrared radiation causing the atmosphere to warm. All these gasses are increasing in concentration in the atmosphere and some have a greater effect on climate change than CO2.
The current concentration of CO2 is 380 ppm (parts per million). The Inter Governmental Panel on Climate Change estimates that atmospheric CO2 will reach somewhere between 541 and 970 ppm by 2100. Perhaps the most worrying figure comes from the Australian led Global Carbon Project. They estimate that the rate at which CO2 concentration is growing has risen from 1.49 ppm per year in 1900-1999 to 2.05 ppm per year in 2000-2005.
How much warmer will it get?
The short answer is, we do not know how much warmer the world will get because the atmosphere is part of a very complicated system. So complicated in fact, that not all effects and influences are fully understood and scientists must make some estimates when modelling the future.
We do know that there is variation in the Earth's climate as evidenced by regular Ice Ages punctuated by warmer inter-glacial periods. During ice ages CO2 levels drop to less than 200 parts per million (ppm) and during the warmest period of the past 650,000 years they rose to 300 ppm. The current concentration of CO2 is 380 ppm, the highest concentration in the last 600,000 years and probably the highest in the last 20 million. The Earth's average temperature has risen from 15.1°C in the 1940's to 15.7°C today and the rate of warming is increasing.
Climate models are very complex and their results vary, however there is a growing consensus that atmospheric changes will result in global warming of between 1.4°C - 5.8°C by 2100. However there are several factors hidden in these figures:
- Warming over land may be significantly higher than the global average - temperature rises over the seas will likely be less than the average
- Warming will likely continue well past 2100 and the final figure could therefore be higher
It is also important to understand that while there are several unknowns estimated within climate models there are several major unknowns which climate modellers don't even try to tackle. These factors may create change outside this predicted envelope.
What will the impacts be?
What is Earthwatch Australia doing?
Carbon Offsetting