Observing & Predicting

We're nine laps into the race to set a new global annual temperature record. NOAA climate scientist Deke Arndt talks about how this year's race might end--and why yearly rankings tell us less about the big picture of climate change than we might think.

Tuesday, September 1, 2009

  •  The Sun is the main source of power for the Earth's climate machine. Space-based measurements, begun in 1978, indicate Earth receives an average of 1,361 W/m<sup>2</sup> of incoming sunlight, and the amount varies by about one-tenth of a percent over the course of the 11-year solar cycle.