Earths Recent Climate History Climate evolution over the last 65 - - PowerPoint PPT Presentation

Temperature evolution over the last 110 million years from the benthic

• xygen isotopic records (filled colored circles) from Lunt et al. (2016).

Earth’s Recent Climate History

406 ppm Atmospheric carbon dioxide levels from Vostok ice core and more recently from Mauna Loa measurements from Climate Central. CO2 levels haven’t been as high as today in millions of years! Climate evolution over the last 65 million years (www.alpineanalytics.com/Climate/DeepTime.html). Warm, ice‐free times correspond to times of high atmospheric CO2. Cooling and ice sheet formation correspond to a long‐term reduction in atmospheric CO2.

Warm worlds in Earth’s past

Artist’s impression of the Arctic (Denali National Park) landscape and duck‐billed dinos in the Maastrichtian (about 70 million years ago).

Global Climate Models

Paleoclimate simulations of the Cretaceous and comparison with geologic data (from Tabor et al., 2016).

Gardiner, OR

MAT = 11.6°C

Columbus, OH

MAT = 11.6°C

Walnut Creek, AZ

MAT = 11.6°C

What does Mean Annual Temperature really mean?

Red = temperature, blue = precipitation

Mean vs. Variance Changes

Interactions between the Physical and Biological Parts of the Earth are Complex

(NRC, 2012)