Humans and Ecology: What are we doing, what should we do, what can we do, and does it matter?

Why are species going extinct?

The complex molecules that comprise organisms are based on carbon

Fig Carbon cycle

Solar energy: incoming and outgoing

CO 2 and other greenhouse gases keep heat from radiating back into space

CO 2 levels in Hawaii and average global temp. Fig 55.21

Aren't these temperature increases just because of increased urbanization? Fig 55.21

Aren't these temperature increases just because of increased urbanization?

A poorly sited temperature sensor in Marysville, California. The sensor is situation right next to an asphalt parking lot, instead in the middle of a grassy field, as it is supposed to be. The sensor is also adjacent to several several air conditioners that blow their exhaust into the air nearby.

Annual average maximum and minimum unadjusted temperature change calculated using (c) maximum and (d) minimum temperatures from good and poor exposure sites (Menne 2010).

Poor sites showed a cooler maximum temperature compared to good sites.

For minimum temperature, the poor sites were slightly warmer.

The net effect was a cool bias in poorly sited stations

Gases trapped in ice core bubbles can tell us about past climate conditions.

Recent increases in global temperature have reversed a slight cooling trend

Vikings in Greenland in the ’s

As the climate cooled, the Vikings were forced to abandon their outposts

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Effects of global warming are already visible html

~500 m people ~300 m people ~2.5 b people Relative contributions to Global Warming

Humans and Ecology: What are we doing, what should we do, what can we do, and does it matter?