2 August Show (0:00 to 12:52)Tweet
Media Source: AAAS
Program Name: Science Podcast
Show Name: 2 August Show (0:00 to 12:52)
Broadcast Year: 2013
Original Link: http://www.sciencemag.org/content/341/6145/574.2.full
The Cenozoic time period is referred to as a mean climate state, because it existed over millions of years when the whole ecosystem was in equilibrium with very high CO2 levels. The present climate state is a transient state, which is a rapid transition from relatively cool climates to warmer climates. During rapid change, parts of the Earth’s ecosystem do not respond at the same rates, such as the surface land heating quickly but the oceans remaining cooler. Although, referring back to the mean climate state gives us a sense of how the world works when in equilibrium with high CO2 levels. For example, oceans were much warmer then than they are now, which led to a much less oxygenated ocean. Sea levels were about 50 meters higher, and coral algal reefs really did not exist during the peak of greenhouse warming. This phenomenon is being observed today, at much very slow rates. Oceanic food chains were also impacted, becoming much longer with high CO2 levels. This means smaller bacteria and algae are at the base of the chain and the smaller base simply does not provide enough energy to support larger animals at the top. However, tectonic passageways that exist today that did not exist in the past will likely prevent this food chain depletion. Overall, in using examples from the past researchers are predicting possible climate change outcomes in the future.