What are the most important factors influencing climate change?
In addition to greenhouse gases, a primary factor in climate change is the relationship between the Earth and Sun. How the Earth handles energy output from the sun changes with the Earth’s surface whiteness expansion and contraction of everything from ice sheets and glaciers to snowpack and sea ice. It changes with ocean circulation how long the ocean holds chemicals, affecting its capture or release of heat. Along with the ocean, atmospheric circulation transports heat and moisture. If we didn’t have a change in greenhouse gases, what we would be most concerned about is atmospheric circulation. How do we know which climate changes are natural and which are human-induced? To make that determination, you need records that are long enough to help you understand how the natural system operates. Records for the northern hemisphere demonstrate that temperatures for the last couple of decades are warmer than for the last thousand years at least, but there have also been times between the 194
