he signs of a warming planet are all around us: rising seas, melting ice sheets,
record-setting temperatures, with impacts cascading to ecosystems, humans,
and our economy. At the root of the problem, anthropogenic greenhouse gas
emissions to the atmosphere continue to increase, a substantial fraction of which diffuse
into the ocean, causing ocean acidification and threatening marine ecosystems.
Global climate is changing faster than at any time since the rise of human civilization,
challenging society to adapt to those changes. If the current dependence on fossil fuel
use continues, evidence from previous periods of high atmospheric greenhouse gas
concentrations indicates that our release of fossil fuel carbon into Earth’s atmosphere
in the form of CO2 will be recorded in the rock record as a major planet-wide event,
marked by transgressions of shorelines, extinctions of biota, and perturbations of major
biogeochemical cycles.