Earth’s Energy BalanceEarth’s Energy Balance

The role of the Sun and The role of the Sun and atmosphere in establishing atmosphere in establishing

Earth’s surface Earth’s surface temperaturetemperature

Energy FlowEnergy FlowTo solve a crime you “follow the money”; to To solve a crime you “follow the money”; to

understand many environmental problems, understand many environmental problems, “follow the energy.”“follow the energy.”

Energy changes form but the total amount Energy changes form but the total amount is always conserved.is always conserved.

Energy eventually “degrades” into heat.Energy eventually “degrades” into heat. A place reaches a higher temperature A place reaches a higher temperature

when energy spends more time there—but when energy spends more time there—but just as much energy is always emitted as just as much energy is always emitted as is absorbed. is absorbed.

Energy Balance DiagramEnergy Balance Diagram

Solar Insolation:Solar Insolation:The Sun in JanuaryThe Sun in January

Solar Insolation:Solar Insolation:The Sun in JuneThe Sun in June

Vostok Ice Cores Vostok Ice Cores and Milankovitch Cyclesand Milankovitch Cycles

Solar ActivitySolar Activity Sunspot number measures of solar activity.Sunspot number measures of solar activity. Sun is actually brighter when more active.Sun is actually brighter when more active. In Maunder Minimum (shortly after Galileo) In Maunder Minimum (shortly after Galileo)

Sun was less active and Earth was cooler.Sun was less active and Earth was cooler.

Solar Variations and ClimateSolar Variations and Climate

Most climatologists’ models conclude solar Most climatologists’ models conclude solar variations alone cannot explain current amount variations alone cannot explain current amount of warming.of warming.

Earth Radiation Budget ExperimentEarth Radiation Budget ExperimentWhat comes out must go inWhat comes out must go in

Solar Energy PotentialSolar Energy Potential

The Carbon The Carbon CycleCycle

The Earth is a The Earth is a closed systemclosed system for carbonfor carbon

Recycling of Recycling of carbon takes carbon takes place on many place on many different time different time scales.scales.

Carbon Dioxide HistoryCarbon Dioxide HistoryPollutants are causing changes in trace moleculesPollutants are causing changes in trace molecules