The United Nations Framework Convention on Climate Change offers the defintion of global warming as "a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods." Expanding further, the "climate system" means the "totality of the atmosphere, hydrosphere, biosphere, and geosphere and their interactions."
The UNFCCC formed more than 20 years ago with the goal of reversing the dangerous effects of global warming, most of which can be achieved through the reduced use of greenhouse gases.
VOTE NOW: Are You Concerned About Global Warming?
There is no easy fix for a problem that has been more than a century in the making, and the issue affects the entire planet. The main response remains lowering emissions.
In 2010, the world's governments agreed that emissions need to keep global temperature increases at below two degrees Celsius.
In March 2013, the World Meteorological Organization, a United Nations agency with nearly 200 member states and territories (as of January 2013),
issued their climate change report. Their findings indicated a "strong scientific consensus that the global climate is changing and that human activity contributes significantly," and "human-induced climate change is caused by greenhouse gas emissions from industry, transport, agriculture, and other vital economic sectors."
Eleven of the world's leading national science academies — representing Brazil, Canada, China, France, Germany, Italy, India, Japan, Russia, the U.K., and the U.S. — signed a joint statement in 2005 attesting to those same conclusions.
UNEP states its mission as one "to provide leadership and encourage partnership in caring for the environment by inspiring, informing, and enabling nations and peoples to improve their quality of life without compromising that of future generations." Through its initiatives, UNEP aspires to be the authority that establishes the "global environmental agenda."
URGENT: Do You Think Global Warming Is a Hoax? Vote Here Now!