Climate change 101: understanding and responding to global climate change
Climate Change Resilience, Island and Ocean Ecosystems
Available Online
PEW Center on Global Climate Change
2009
Scientists state unequivocally that the earth is warming. Climate change is happening, it is caused in large part by human activity, and it will have many serious and potentially damaging effects in the decades ahead. Greenhouse gas emissions from cars, power plants, and other human activitiesrather than natural variations in climateare the primary cause of contemporary global warming. Due largely to the combustion of fossil fuels, atmospheric concentrations of carbon dioxide (CO2), the principal greenhouse gas, are at a level unequaled for at least 800,000 years. The greenhouse gases from human activities are trapping more of the suns heat in the earths atmosphere, resulting in warming. Over the last century, average global temperatures rose by more than 1°F and some regions warmed by as much as 4°F. The oceans have also warmed, especially in the upper layers.