How the greenhouse effect works, explained in a graphic from the exhibition. Click the image to see a larger version.
AMNH
A transparent, protective blanket envelops Earth. It is the atmosphere, which admits enough of the energy streaming from the Sun to warm our planet and retains enough of that heat to keep it livable. The heat-holding process is called the greenhouse effect. In its absence, Earth's surface temperature would be -18o C (0o F). There would be no liquid water --and no life on the surface.
Lately, though, we've been changing the makeup of our insulating blanket. Human activity, particularly burning fossil fuels, creates greenhouse gases. And one of those gases--carbon dioxide (CO2)--has now reached levels not seen for at least 800,000 years, and probably much longer.
Greenhouse gases trap heat - Higher concentrations mean a warmer earth.
Here's why:
- Energy from coal creates more CO2 than the same amoung of energy from other fossil fuels.
- Coal isn't the only source of CO2 -- and CO2 isn't the only greenhouse gas we're producing.
