The concentration of greenhouse gases in the atmosphere has increased substantially since the Industrial Revolution, at a pace that is accelerating exponentially in the modern day. Global net emissions of greenhouse gases—carbon dioxide, methane and others that trap heat in the atmosphere— increased 35% from 1990 to 2010.
Increases in the concentration of greenhouse gases in the environment have atmospheric warming effects. Scientists have been able to infer previous global temperatures from studying the water vapor released by melting dated ice cores, and have concluded that mean global temperature is the warmest it has been in tens of thousands of years, with levels of carbon dioxide surpassing anything observed in the past millions of years. These changes in atmospheric levels are largely attributable to human activities since the Industrial Revolution.