September 27, 2013
Humans Are Main Cause Of Climate Change, Says UN Report
[ Watch The Video: Temperature And Precipitation In The 21st Century ]
Brett Smith for redOrbit.com - Your Universe Online
"Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes," said the report, which was released Friday morning in Stockholm, Sweden.
The report added that "each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850" and that in "the Northern Hemisphere, 1983–2012, was likely the warmest 30-year period of the last 1400 years."
Skeptics of global warming tend to cite a recent slowing of rising temperatures that has been occurring since 1998. However, the report said this ‘pause’ could be due to changing climate models and called for further study.
"Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends," the report explained.
Qin Dahe, co-chair of the IPCC working group that produced the report, said the panel’s assessments are based on “multiple lines of independent evidence.”
One of those lines of evidence was a series of climate data visualizations called the Coupled Model Intercomparison Project Phase 5 (CMIP5), which included climate models from NASA's Scientific Visualization Studio at Goddard Space Flight Center in Greenbelt, Maryland.
“Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased,” Dahe said.
Thomas Stocker, another co-chair of the group, said that climate change "challenges the two primary resources of humans and ecosystems, land and water. In short, it threatens our planet, our only home.”
A report recently published in the journal Nature Climate Change put the potential impacts of climate change and carbon emissions in the context of costs. The report concluded that over 500,000 lives could be saved each year by 2030 if nations around the world took actions to mitigate climate change. The economics of this health benefit exceeds the costs of forcing nations to drop their fossil fuel emissions, the study added.
The study researchers noted that the cost benefit would be especially true for China, where the gain would equal 10 to 70 times the cost of cutting greenhouse gas emissions. The team noted that their study attempts to quantify the benefits of taking action.
"Neglecting the air quality co-benefits misses an important component of the benefits of reducing greenhouse gas emissions," study author Jason West, assistant professor of environmental sciences and engineering at the University of North Carolina told National Geographic.
"We show those benefits are large enough that they should be part of the analysis, and it should give extra motivation for people to think about why we should be taking action to slow climate change."