The IPCC is a scientific, intergovernmental body, set up at the request of member governments. First established in 1988 by two United Nations (UN) organisations, the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP), the IPCC was later endorsed by the UN General Assembly. The IPCC's mission is to provide comprehensive scientific assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its environmental and socio-economic consequences, and possible action for adaptation and mitigation of the effects of climate change. On a voluntary basis and without payment from the IPCC, thousands of scientists and other experts have contributed to the research, writing, and review of IPCC's reports, which are reviewed by governments of more than 120 countries.
The IPCC's latest landmark Report states that scientists are 95% certain that humans are the “dominant cause" of global warming since the 1950s, saying that the human impact on the environment is “unequivocal." The Fifth Assessment Report reaches a number of conclusions all pointing to the critically urgent need for humanity to reverse the burdening of earth's atmosphere with carbon pollution:
Many of the observed changes since the 1950s are unprecedented over decades to millennia.
Each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850.
Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010.
Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continue to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continue to decrease in extent.
The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia.
Atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in a least the last 800,000 years. CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions such as deforestation. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.
Human influence on the climate system is irrefutable. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.
Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
Cumulative emissions of carbon dioxide largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present, and future emissions of CO2.
The Fifth Assessment Report (AR5) has just been completed during all-night sessions in Stockholm, with the world's leading climate scientists united in their conclusion that climate change is occurring and as a result of human actions. The AR5 is the result of nearly seven years of new research on the climate, and is the IPCC's starkest warning yet that even if the world begins to moderate greenhouse gas emissions, warming is likely to cross the critical threshold of 2 degrees centigrade by the end of this century. This temperature rise will have increasingly deadly consequences for life on earth, including heat waves, droughts, flooding, extreme storms, and widespread extinction of species.
U.S. Secretary of State John Kerry said in response to the report's release: “This is yet another wakeup call: those who deny the science or choose excuses over action are playing with fire. Once again, the science grows clearer, the case grows more compelling, and the costs of inaction grow beyond anything that anyone with conscience or commonsense should be willing to even contemplate. With those stakes, the response must be all hands on deck. It's not about one country making a demand of another. It's the science itself, demanding action from all of us. The United States is deeply committed to leading on climate change."
The IPCC Fifth Assessment Report emphasised for the first time that the world cannot afford to keep emitting carbon dioxide at current levels. To avoid even worse levels of warming, beyond 2C, human beings can only emit a total of between 800-880 gigatonnes of carbon. By 2011, humans had already emitted 530 gigatonnes. Former UN commissioner Mary Robinson said that this fact will have “huge implications for social and economic development," and will be difficult for business interests to accept.
UN Secretary-General Ban Ki-moon introduced the IPCC report to the UN General Assembly on Friday, saying that the unequivocal message from climate scientists clear. The Secretary-General added his own plea: “The heat is on. We must act."
International Climate Activist Bill McKibben And 350.org Support The Leave Me Alone Campaign.
Fifth Assessment Report (AR5).
Author: Jennifer Scarlott
Sources: IPCC Fifth Assessment Report, The Guardian.
