Bg cuts in greenhouse gas emissions needed to avert disaster
FRISCO— It’s becoming more clear that global warming is an existential issue for humanity, threatening to unravel the ecosystems that sustain us.
Without quick and big cuts in greenhouse gases, climate change “will increase the likelihood of severe, pervasive and irreversible impacts,” the Intergovernmental Panel on Climate Change said in its latest report, release Nov. 2, 2014. To prevent warming beyond the 2 degree Celsius target, greenhouse gas emissions must be cut by 40 to 70 percent globally by 2050, and to zero by 2100.
“We have that opportunity, and the choice is in our hands,” IPCC chair R. K. Pachauri, said in a prepared statement.
Along with cutting heat-trapping pollution, an aggressive mitigation strategy can help keep climate change impacts in a manageable range, the panel concluded. The Synthesis Report distils and integrates the findings of the IPCC Fifth Assessment Report produced by over 800 scientists and released over the past 13 months.
“We have the means to limit climate change,” Pachauri said. “The solutions are many and allow for continued economic and human development. All we need is the will to change, which we trust will be motivated by knowledge and an understanding of the science of climate change.”
The Synthesis Report confirms that climate change can be observed around the world, and that warming of the climate system is unequivocal. Since the 1950s many of the observed changes are unprecedented over decades to millennia.
“Our assessment finds that the atmosphere and oceans have warmed, the amount of snow and ice has diminished, sea level has risen and the concentration of carbon dioxide has increased to a level unprecedented in at least the last 800,000 years,” said Thomas Stocker, Co-Chair of IPCC Working Group I.
The report expresses with greater certainty than in previous assessments the fact that emissions of greenhouse gases and other anthropogenic drivers have been the dominant cause of observed warming since the mid-20th century.
The impacts of climate change have already been felt in recent decades on all continents and across the oceans. The more human activity disrupts the climate, the greater the risks. Continued emissions of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of widespread and profound impacts affecting all levels of society and the natural world, the report finds.
The Synthesis Report makes a clear case that many risks constitute particular challenges for the least developed countries and vulnerable communities, given their limited ability to cope. People who are socially, economically, culturally, politically, institutionally, or otherwise marginalized are especially vulnerable to climate change.
“Many of those most vulnerable to climate change have contributed and contribute little to greenhouse gas emissions,” Pachauri said. “Addressing climate change will not be possible if individual agents advance their own interests independently; it can only be achieved through cooperative responses, including international cooperation.”
“Adaptation can play a key role in decreasing these risks,” said Vicente Barros, Co-Chair of IPCC Working Group II. “Adaptation is so important because it can be integrated with the pursuit of development, and can help prepare for the risks to which we are already committed by past emissions and existing infrastructure.”
But adaptation alone is not enough. Substantial and sustained reductions of greenhouse gas emissions are at the core of limiting the risks of climate change. And since mitigation reduces the rate as well as the magnitude of warming, it also increases the time available for adaptation to a particular level of climate change, potentially by several decades.
“It is technically feasible to transition to a low-carbon economy,” said Youba Sokona, Co-Chair of IPCC Working Group III. “But what is lacking are appropriate policies and institutions. The longer we wait to take action, the more it will cost to adapt and mitigate climate change.”
These economic estimates of mitigation costs do not account for the benefits of reduced climate change, nor do they account for the numerous co-benefits associated with human health, livelihoods, and development.
“The scientific case for prioritizing action on climate change is clearer than ever,” Pachauri said. “We have little time before the window of opportunity to stay within 2 degrees Celsius of warming closes.