Wednesday, 27 June 2012

US Court says: "This is how science works"

The NCSE have reported that:
A federal court rejected a claim that the evidence for climate change is too uncertain for the United States government to act on it.
This is good news for science, because the judges have supported regulators who defer to scientific authority when implementing policy. The US Environmental Protection Agency had ruled, based on climate science studies collated by the IPCC and other authorities, that the Clean Air Act required Federal Government to impose limits once it determined emissions were harmful. Presumably petitioners wanted to cast doubt on the link between climate changes and emissions, so that, if harmful environmental changes were detected, this would not result in limits being placed on their operations.

A key paragraph in the judgement is this:

State and Industry Petitioners assert that EPA improperly “delegated” its judgment to the IPCC, USGCRP, and NRC by relying on these assessments of climate-change science. See U.S. Telecom Ass’n v. FCC, 359 F.3d 554, 566 (D.C. Cir. 2004). This argument is little more than a semantic trick. EPA did not delegate, explicitly or otherwise, any decision-making to any of those entities. EPA simply did here what it and other decision makers often must do to make a science-based judgment: it sought out and reviewed existing scientific evidence to determine whether a particular finding was warranted. It makes no difference that much of the scientific evidence in large part consisted of “syntheses” of individual studies and research. Even individual studies and research papers often synthesize past work in an area and then build upon it. This is how science works. EPA is not required to re-prove the existence of the atom every time it approaches a scientific question.
This is not to say that the science is right, but it is to say that deferring to the appropriate scientific authority is right. If the petitioners want to call this a judgement 'delegated', then fine; but it's the right way to conduct public policy. Of course 'delegated' suggests that the EPA simply washed its hands of responsibility for the science, but without reproving the existence of the atom, there is still much that needs to be done, and can be done:
Moreover, it appears from the record that EPA used the assessment reports not as substitutes for its own judgment but as evidence upon which it relied to make that judgment. EPA evaluated the processes used to develop the various assessment reports, reviewed their contents, and considered the depth of the scientific consensus the reports represented. Based on these evaluations, EPA determined the assessments represented the best source material to use in deciding whether greenhouse gas emissions may be reasonably anticipated to endanger public health or welfare. Endangerment Finding, 74 Fed. Reg. at 66,510–11. It then reviewed those reports along with comments relevant to the scientific considerations involved to determine whether the evidence warranted an endangerment finding for greenhouse gases as it was required to do under the Supreme Court’s mandate in Massachusetts v. EPA.
The very act of relying on the science can be, and should be, approached in a scientific manner. A sensible government agency will gauge the level of confidence it can take from the nature of the evidence and the outcome of studies and meta-studies, without re-doing those studies themselves. As the judgement says:

Based on this scientific record, EPA made the linchpin finding: in its judgment, the “root cause” of the recently observed climate change is “very likely” the observed increase in anthropogenic greenhouse gas emissions. Endangerment Finding, 74 Fed. Reg. at 66,518. EPA found support for this finding in three lines of evidence. First, it drew upon our “basic physical understanding” of the impacts of various natural and manmade changes on the climate system. For instance, EPA relied on evidence that the past half-century of warming has occurred at a time when natural forces such as solar and volcanic activity likely would have produced cooling. Endangerment Finding, Response to Comments (RTC) Vol. 3, at 20. Other evidence supports EPA’s conclusion that the observed warming pattern—warming of the bottommost layer of the atmosphere and cooling immediately above it—is consistent with greenhouse-gas causation.
EPA further relied upon evidence of historical estimates of past climate change, supporting EPA’s conclusion that global temperatures over the last half-century are unusual. Endangerment Finding, 74 Fed. Reg. at 66,518. Scientific studies upon which EPA relied place high confidence in the assertion that global mean surface temperatures over the last few decades are higher than at any time in the last four centuries. Technical Support Document for the Endangerment Finding (TSD), at 31. These studies also show, albeit with significant uncertainty, that temperatures at many individual locations were higher over the last twenty-five years than during any period of comparable length since 900 A.D.
For its third line of evidence that anthropogenic emissions of greenhouse gases spurred the perceived warming trend, EPA turned to computer-based climate-model simulations. Scientists have used global climate models built on basic principles of physics and scientific knowledge about the climate to try to simulate the recent climate change. These models have only been able to replicate the observed warming by including anthropogenic emissions of greenhouse gases in the simulations. Endangerment Finding, 74 Fed. Reg. at 66,523.

A cautionary note, however; Mitt Romney's plan, according to his website, is to "Amend Clean Air Act to exclude carbon dioxide from its purview", which would be an odd thing to do; like excluding smoke from the Clean Air Act. If he was successful, this would render this judgement irrelevant, and no limits based on the Clean Air Act could be placed on industry in the US to curb climate change.


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