New Climate Sensitivity Report May Impact Climate Policy Debate
If the IPCC can no longer give a central climate sensitivity estimate, can the Obama administration credibly peg a price to carbon dioxide emissions?
The United Nations doesn’t want you to know the facts about global warming, according to a new report out of Europe.
Over the years climate scientists have been reducing their estimates of how much global warming will occur over the next 70 to 100 years if atmospheric carbon dioxide concentrations were doubled — an estimate called “climate sensitivity.”
But readers of the most recent UN Intergovernmental Panel on Climate Change (IPCC) assessment would be ignorant of this, according to a report by the UK’s Global Warming Policy Foundation.
But this revelation was only hinted at in the IPCC’s 2013 climate assessment. Instead of lowering their central climate sensitivity measure down from 3 degrees Celsius, the IPCC simply did not give a central estimate and just reduced its lower-bound warming estimate from 2 to 1.5 degrees Celsius. Now the IPCC’s warming range for the next hundred years is 1.5 to 4.5 degrees Celsius. [...]
Climate sensitivity is used by policymakers to predict global temperature increases and economic costs, and therefore is a crucial estimate to nail down. In the U.S., the Obama administration is using the UN’s climate sensitivity measures to come up with its “social cost of carbon” (SCC) estimate, which applies monetary damages to each ton of carbon dioxide emitted into the atmosphere.
Last year, the Obama administration raised the SCC from from $21 per ton to $37 per ton before the president went public with his plans to cut U.S. emissions 17 percent by 2020. Raising the SCC inflates the benefits of policies that reduce carbon emissions, therefore, giving more justification to Obama’s fight against global warming.
“The shift to a cleaner energy economy won’t happen overnight, and it will require tough choices along the way,” Obama said in his 2014 State of the Union Address. “But the debate is settled. Climate change is a fact. And when our children’s children look us in the eye and ask if we did all we could to leave them a safer, more stable world with new sources of energy, I want us to be able to say, ‘Yes, we did.’”
But the recent GWPF report casts doubt on Obama’s justification for raising the SCC to $37 per ton, as it was based on the UN’s misleading climate assessment. If the IPCC can no longer give a central climate sensitivity estimate, can the Obama administration credibly peg a price to carbon dioxide emissions?
“It should be obvious that no SCC estimates should be published until a credible climate sensitivity probability distribution is developed,” wrote attorney Francis Menton in his comments to the White House on the SCC changes. “This multi- agency effort has relied on the IPCC work, but IPCC’s own results imply that the U.S. government should stop publishing any estimates of SCC until such a credible distribution exists.”
The Obama administration, however, has showed no indication that it intends to scale back its SCC estimate or scrap it altogether.