Global warming is “unequivocal” and humans are turning up the heat — but more slowly since 1998, according to a report from the United Nations Intergovernmental Panel on Climate Change released today.
Each of the last three decades has been warmer at the Earth’s surface than any previous decade since 1850, says the 36-page Summary for Policymakers of the IPCC Working Group’s assessment report, approved today by IPCC member governments in Stockholm. In the Northern Hemisphere, 1983–2012 was “likely” the warmest 30-year period of the last 1400 years.
The atmosphere and oceans have warmed, snow and icecaps diminished, sea levels have risen and concentrations of greenhouse gasses (CO2, methane and nitrous oxide) have increased since 1750 due to human activity, the report concludes.
But the rate of warming over the past 15 years (from 1998 to 2012) is slower than the rate calculated since 1951, according to the assessment. Average global temperatures rose at 0.05 degree Celsius per decade from 1998 through 2012, compared to 0.12 degree per decade from 1951 through 2012. This 15-year slow down in temperature increases, however, does not reflect long-term climate trends, the report says.
Global surface temperature change by the end of the 21st century will likely exceed 1.5 degrees Celsius, relative to 1980 to 1900, in all but the lowest scenarios considered by scientists, and will likely exceed 2 degrees Celsius for the two highest scenarios.
The assessment also says the rate of global sea level rise will “very likely” exceed the rate observed between 1971 and 2012. It attributes this to hotter ocean temperatures and melting glaciers and ice sheets.
Limiting climate change will require “substantial and sustained” GHG reductions, says Thomas Stocker, co-chair of the working group.
Ceres says the IPCC report confirms climate change is affecting businesses' bottom lines and their strategies.
VF Corporation — one of the world's largest single purchasers of cotton, whose brands include Lee, Wrangler and The North Face — says much of the world’s cotton comes from areas that are expected to be impacted most by water scarcity and extreme weather such as the Western US, China, Pakistan and India. The IPCC report makes firms' risks associated with climate change even more clear, says Letitia Webster, VF’s director of global corporate sustainability.
Climate change hurts VF’s outdoor and recreation brands, Webster says: “Whether in mountains or the ocean, our brands and our consumers are feeling the impacts of climate change,” which means less ski-related business for The North Face. The company today signed Ceres’ Climate Declaration, calling on US policymakers to enact climate and clean energy policies that will benefit the economy.
Financial firm HSBC echoed the IPCC report’s conclusions by issuing two separate reports of its own in recent days. It's research shows that India, China, Indonesia, South Africa and Brazil are the G-20 nations whose economies are most vulnerable to climate risks, including rising sea levels and melting glaciers. The IPCC report "provides firmer foundations for policy action," says Nick Robins, head of the Climate Change Centre at HSBC.
Mark Way, who heads reinsurer Swiss Re’s sustainability work in the Americas, says it would be "foolish" not to listen to IPCC's conclusion that it's 95 percent likely that mankind is causing climate change. Transitioning to a low carbon economy is not an option, it's a necessity, Way says. To this end, Swiss Re will join an initiative that pledges companies to source 100 percent of their energy needs from renewable sources by 2020.
If US businesses act now to reduce GHG emissions by an average of 3 percent annually, they can save up to $190 billion in 2020 alone, or $780 billion over 10 years, according to a report published in June by World Wildlife Fund and CDP.
Environmental Groups praised the IPCC report, saying it represents a call to action. Steve Hamburg, Environmental Defense Fund chief scientist, said the EPA’s proposed carbon pollution limits for new power plants are “good steps in the right direction” and the Natural Resources Defense Council called the new power plant rules “critical” to addressing global warming.
