Judith Curry interview on climate change

The IPCC May Have Outlived its Usefulness

 Some extracts:

 OP: What are your personal beliefs on climate change? The causes and how serious a threat climate change is to the continued existence of society as we know it.

 JC: The climate is always changing. Climate is currently changing because of a combination of natural and human induced effects. The natural effects include variations of the sun, volcanic eruptions, and oscillations of the ocean. The human induced effects include the greenhouse gases such as carbon dioxide, pollution aerosols, and land use changes. The key scientific issue is determining how much of the climate change is associated with humans. This is not a simple thing to determine. The most recent IPCC assessment report states: “Most [50%] of the warming in the latter half of the 20th century is very likely [>90%] due to the observed increase in greenhouse gas concentrations.” There is certainly some contribution from the greenhouse gases, but whether it is currently a dominant factor or will be a dominant factor in the next century, is a topic under active debate, and I don’t think the high confidence level [>90%] is warranted given the uncertainties.

 As I stated in my testimony last year: “Based upon the background knowledge that we have, the threat does not seem to be an existential one on the time scale of the 21st century, even in its most alarming incarnation.”

OP: You are well known in climate and energy circles for breaking from the ranks of the IPCC and questioning the current information out there. What do you see as the reasons for the increase in skepticism towards global warming over the last few years.

JC: Because of the IPCC and its consensus seeking process, the rewards for scientists have been mostly in embellishing the consensus, and this includes government funding. Because of recent criticisms of the IPCC and a growing understanding that the climate system is not easily understood, an increasing number of scientists are becoming emboldened to challenge some of the basic conclusions of the IPCC, and I think this is a healthy thing for the science.

OP. What are your views on the idea that CO2 may not be a significant contributor to climate change? How do you think such a revelation, if true, will affect the world economy, and possibly shatter public confidence in scientific institutions that have said we must reduce CO2 emissions in order to save the planet?

JC: Personally, I think we put the CO2 stabilization policy ‘cart’ way before the scientific horse. The UN treaty on dangerous climate change in 1992 was formulated and signed before we even had ‘discernible’ evidence of warming induced by CO2, as reported in 1995 by the IPCC second assessment report. As a result of this, we have only been considering one policy option (CO2 stabilization), which in my opinion is not a robust policy option given the uncertainties in how much climate is changing in response to CO2.

OP: Do you believe that the language used in papers and at conferences is a problem? The public just wants straight answers to questions: Is the climate warming, By how much, and what will the effects be? Scientists need to step out from behind the curtain and engage the public with straight answers and in their own words. Is this achievable, or is climate science too complex to be explained in laymen’s terms? Or is it because even climate scientists can’t agree on the exact answers?

JC: I think the biggest failure in communicating climate science to the public has been the reliance on argument from consensus. We haven’t done a good job of explaining all this, particularly in the context of the scientific disagreement

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