Judith Curry's evaluation of the climate change debate

Judith Curry's testimony to The House of Representatives Committee on Science, Space and Technology Full Committee Hearing about The President’s UN Climate Pledge: Scientifically Justified or a New Tax on Americans?

Here is the [link] for the hearing, which includes link to all of the testimonies and also the webcast

Judith Curry (blog):

The central issue in the scientific debate on climate change is the extent to which the recent (and future) warming is caused by human-caused greenhouse gas emissions versus natural climate variability that are caused by variations from the sun, volcanic eruptions, and large-scale ocean circulations.

Recent data and research supports the importance of natural climate variability and calls into question the conclusion that humans are the dominant cause of recent climate change. This includes:

• The slow down in global warming since 1998 
• Reduced estimates of the sensitivity of climate to carbon dioxide 
• Climate models that are predicting much more warming than has been observed so far in the 21st century

While there are substantial uncertainties in our understanding of climate change, it is clear that humans are influencing climate in the direction of warming. However this simple truth is essentially meaningless in itself in terms of alarm, and does not mandate a particular policy response.

We have made some questionable choices in defining the problem of climate change and its solution:

• The definition of ‘dangerous’ climate change is ambiguous, and hypothesized catastrophic tipping points are regarded as very or extremely unlikely in the 21st century
• Efforts to link dangerous impacts of extreme weather events to human-caused warming are misleading and unsupported by evidence.
• Climate change is a ‘wicked problem’ and ill-suited to a ‘command and control’ solution
• It has been estimated that the U.S. national commitments to the UN to reduce emissions by 28% will prevent three hundredths of a degree centigrade in warming by 2100.

The inadequacies of current policies based on emissions reduction are leaving the real societal consequences of climate change and extreme weather events largely unaddressed, whether caused by humans or natural variability.

The wickedness of the climate change problem provides much scope for disagreement among reasonable and intelligent people. Effectively responding to the possible threats from a warmer climate is made very difficult by the deep uncertainties surrounding the risks both from the problem and the proposed solutions.

The articulation of a preferred policy option in the early 1990’s by the United Nations has marginalized research on broader issues surrounding climate variability and change and has stifled the development of a broader range of policy options.

We need to push the reset button in our deliberations about how we should respond to climate change:

• We should expand the frameworks for thinking about climate policy and provide a wider choice of options in addressing the risks from climate change. 
• As an example of alternative options, pragmatic solutions have been proposed based on efforts to accelerate energy innovation, build resilience to extreme weather, and pursue no regrets pollution reduction 
• Each of these measures has justifications independent of their benefits for climate mitigation and adaptation. 
• Robust policy options that can be justified by associated policy reasons whether or not human caused climate change is dangerous avoids the hubris of pretending to know what will happen with the 21st century climate.

This concludes my testimony.

Judith also recommends reading the testimonies of Harbert and Thorning