HumanāInduced Climate Change Requires Urgent Action Humanity is the major influence on the global climate change observed over the past 50 years. Rapid societal responses can significantly lessen negative outcomes. Human activities are changing Earthās climate. At the global level, atmospheric concentrations of carbon dioxide and other heatātrapping greenhouse gases have increased sharply since the Industrial Revolution. Fossil fuel burning dominates this increase. Humanācaused increases in greenhouse gases are responsible for most of the observed global average surface warming of roughly 0.8°C (1.5°F) over the past 140 years. Because natural processes cannot quickly remove some of these gases (notably carbon dioxide) from the atmosphere, our past, present, and future emissions will influence the climate system for millennia.
Extensive, independent observations confirm the reality of global warming. These observations show largeāscale increases in air and sea temperatures, sea level, and atmospheric water vapor; they document decreases in the extent of mountain glaciers, snow cover, permafrost, and Arctic sea ice. These changes are broadly consistent with longā understood physics and predictions of how the climate system is expected to respond to humanācaused increases in greenhouse gases. The changes are inconsistent with explanations of climate change that rely on known natural influences.
Climate models predict that global temperatures will continue to rise, with the amount of warming primarily determined by the level of emissions. Higher emissions of greenhouse gases will lead to larger warming, and greater risks to society and ecosystems. Some additional warming is unavoidable due to past emissions.
http://sciencepolicy.agu.org/files/2013/07/AGU-Climate-Change-Position-Statement_August-2013.pdf
The American Geophysical Union includes more climate scientists than any other scientific society on earth.