Current global temperatures are warmer than they have ever been during at least the past five centuries, probably even for more than a millennium (Jansen et al., IPCC, 2007). The main contributor to this ‘global warming’ is the consistent and perpetual rise of greenhouse gases (GHG) – such as carbon dioxide (CO2) – in our atmosphere. While there has been some debate in the past as to whether this is human-caused or a natural phenomenon, the time for doubt has passed. The International Panel on Climate Change has unequivocally affirmed the warming of our climate system, and linked it directly to human activities, such as transportation (cars and planes), deforestation and industrial processes.
Scientists measure the CO2 in our atmosphere in parts per million (ppm). Over the past 650,000 years CO2 concentration varied between a low of 180 parts per million (ppm) during cold glacial times and a high of 300 ppm during warm interglacials. Over the past century, CO2 levels rapidly increased well out of this range, and are now at 410 ppm. It can take up to 200 years for CO2 to be removed from our atmosphere.
It is widely understood by the global scientific community, that the high levels of C02 in our atmosphere will cause a number of changes to our climate. These include increased atmospheric and oceanic temperatures, ocean acidification, and melting of glaciers and polar ice sheets. This is resulting in higher frequency of extreme weather events, such as drought, fires, and heavy rain events and flooding.
These facts may seem overwhelming, but we all have a responsibility to do our part to combat climate change so that our children and grandchildren have a healthy planet to sustain them.