State of the U.S. Climate Debate

Judith Curry

Georgia Institute of Technology

Climate Forecast Applications Network

science

President Obama’s statements

“We will respond to the threat ofclimate change, knowing that failureto do so would betray our childrenand future generations.”

"No challenge--no challenge--poses a greater threat to future generationsthan climate change."  

“There’s one issue that will define the contours of this century more dramatically than any other, and that is the urgent and growing threat of a changing climate.”

IPCC:

1.Human-caused climate change is real

2.Human-caused climate change is dangerous

3.Action is needed to prevent dangerous human caused climate change

UNFCCC Treaty (1992):

The UNFCCC established a goal of stabilization of atmospheric greenhouse gases to prevent dangerous climate change

Intended Nationally Determined Contributions (INDCs)

U.S. INDC:

•Reduce emissions by 26-28% below 2005 levels by 2025

•Economy-wide emission reductions of 80% by 2050

Environmental Protection Agency (EPA): Clean Power Plan

By 2030, these steps will:•Cut carbon power sector emission by 30% nationwide below 2005 levels

•Cut particle pollution, nitrogen oxides, and sulfur dioxide by more than 25%

•Avoid up to 6,600 premature deaths, up to 150,000 asthma attacks in children;

•Shrink electricity bills 8% by increasing energy efficiency and reducing demand.

EPA Endangerment Finding

• In Massachusetts v. EPA (2007), the Supreme Court held that greenhouse gases are pollutants under the Clean Air Act.

• In 2009, the EPA determined that Greenhouse gas pollution will endanger public health.

State Governors’ perspectives on climate change

Source: ClimateProgress

Selling the President’s Plan (I)

Social Cost of Carbon

Rationale: Assess cost-benefit of regulatory actions that impact CO2 emissions

Challenge:

•Costs and benefits, estimated over 300 years, are highly uncertain and contested•High costs now will damage the economy and development•Social discount rate: how much should we value potential damages to future people?

Selling the President’s Plan (II)

Extreme weather

President Obama: "The best climate scientists in the world are telling us that extreme weather events like hurricanes are likely to become more powerful. Climate change didn't cause Hurricane Sandy, but it might have made it stronger.”

Chris Landsea, NHC: “How is it that the White House links changes in hurricanes today to global warming when WMO, NOAA, and IPCC cannot?”

US landfalling hurricanes

Global tropical cyclone ACE

Are hurricanes made worse by climate change?

Source: Ryan Maue

Source: Roger Pielke Jr

Selling the President’s Plan (III)

Public health benefits

President Obama: “Carbon pollution causing climate change is contributing to health risks for many children. Over the past 3 decades, the % of Americans with asthma has more than doubled and climate change is putting those Americans at greater risk of landing in the hospital”.

Challenge: CO2 does not impact airquality and breathing. U.S. air quality (ozone and particulates) has improvedsubstantially in past 3 decades.

Selling the President’s Plan (IV)

National Security

President Obama: ”Climate change constitutes a serious threat to global security, an immediate risk to our national security, and, make no mistake, it will impact how our military defends our country,”.

Challenge: The main security issue is the impactof extreme weather events, which is better addressed by adaptation. CO2 mitigation is an ineffective national security tool.

As ISIS marches . . .

Reduces global warming

The U.S. INDC of 28% reduction of emissions below 2005 levels by 2025 will prevent 0.03oC in warming by 2100.

Reducing U.S. total emissions by 80% by 2050 will prevent 0.11oC in warming by 2100

Source: CATO

Senator James Inhofe (R) Chair, Env. & Public Works Comm

Rep. Lamar Smith (R)Chair, Science, Space & Tech Comm.

Wall Street Journal op-ed 4/23/15

The Climate-Change ReligionEarth Day provided a fresh opening for Obama to raise alarms about global warming based on beliefs, not science.

Washington Post op-ed 5/19/13

Overheated rhetoric on climate change hurts the economyClimate change is an issue that needs to be discussed thoughtfully and objectively. Unfortunately, claims that distort the facts hinder the legitimate evaluation of policy options.

The ‘treaty’ problem

Article II, Section 2, Clause 2 of the U.S. Constitution includes the Treaty Clause:

“ [The President] shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur . . . “

Sense of the Senate Resolution 1/20/15“Climate change is real and not a hoax” (98-1)

“Climate change is real; and human activity significantly contributes to climate change.” (50-49)___________________

Confusion between the scientific and political definition:

•Scientific defn: Climate change may be due to natural processes, or to persistent anthropogenic changes.

•Political defn equates ‘climate change’ with human-caused climate change (UNFCCC)

Natural climate variability versus human-caused climate change is at the heart ofscientific and policy debate

Impact on the UNFCCC

President Obama intends to sign a UN climate agreement without Congressional approval

French Foreign Minister Laurent Fabius in Bonn:

“We must find a formula which is valuable for everybody and valuable for the U.S. without going to the Congress”

To what extent is President Obama’s Climate Commitment enforceable?

In the absence of state and Congressional support, the Plan is being enforced through the Executive Branch via the Environmental Protection Agency (EPA).

Challenges:•Ongoing legal challenges, but so far the Supreme Court has supported Obama•The next President may choose not to enforce, or even to abolish the EPA.

Republican Presidential Candidates (I)

Jeb Bush: “I don’t think the science is clear of what % is man-made and what % is natural. It’s convoluted. For the people to say the science is decided on this is really arrogant. The climate is changing. We need to adapt to that reality.”

Ted Cruz: “Specifically, satellite data demonstrate there has been no warming over the past 17 years. And I would note whenever anyone makes that point, you immediately get vilified as a ‘denier’ without anyone actually refuting the facts.”

Republican Presidential Candidates (II)

Marco Rubio: “The question is, what percentage of that is due to human activity? If we do the things they want us to do, cap-and-trade, you name it, how much will that change the pace of climate change versus how much will that cost to our economy? “

Carly Fiorina: “The only answer to this is innovation, and in that America could be the best in the world.”

Republican Presidential Candidates (III)

Chris Christie: “when you have over 90% of the world’s scientists who have studied this stating that climate change is occurring and that humans play a contributing role, it’s time to defer to the experts.”

John Kasich: “I am just saying that I am concerned about it, but I am not laying awake at night worrying the sky is falling.”

Rick Santorum: “I for one never bought the hoax. To suggest that man’s contribution is the determining ingredient in the sauce that affects the entire global warming and cooling is just absurd on its face.”

Agreement:•Surface temperatures have increased since 1880•Humans are adding carbon dioxide to the atmosphere•Carbon dioxide and other greenhouse gases have a warming effect on the planet

Disagreement:•Whether the warming since 1950 has been dominated by human causes•How much the planet will warm in the 21st 21st century•Whether warming is ‘dangerous’•Whether we can afford to radically reduce CO2 emissions, and whether reduction will improve the climate

Science in the cross-fire

• President Obama: “We don’t have time for a meeting of the flat earth society.”

• Congressional Republicans: Working on substantial reductions to funding for climate research

Ideologically-fueled research

Many scientists have become advocates for the UNFCCC/IPCC ideology, which is leading scientists into overconfidence in their assessments and public statements and into failures to respond to genuine criticisms of the scientific consensus.

The climate science establishment has become intolerant to disagreement and debate, and is attempting to marginalize and de-legitimize dissent as corrupt or ignorant.

Wall Street JournalFebruary 2, 2006

Cold Front

Debate Shatters Civility of Weather Science

Hurricanes Worsened by Global Warming?

Spats are so tempestuous, sides are barely talking

Charge of “brain fossilization”

Mixing Politics and Science in Testing the Hypothesis That Greenhouse Warming Is Causing a Global Increase in Hurricane Intensity

BY J. A. CURRY, P. J. WEBSTER, AND G. J. HOLLAND

UN IPCC

JC’s concerns: Our core scientific research values became compromised in the “war against the skeptics”:•the rigors of the scientific method (incl reproducibility), •research integrity and ethics •open minds and critical thinking.

Climate Heretic: Judith Curry Turns on Her ColleaguesWhy can't we have a civil conversation about climate?

October 25, 2010

Hiatus (slow down) in global warming

Source: Robert Rohde

Source: UK Climatic Research Unit

El nino

Significance of the ‘hiatus’ since 1998

Growing divergence between models & observations:

•Are climate models too sensitive to greenhouse forcing?

•Is modeled treatment of natural climate variability inadequate?

•Are model projections of 21st century warming too high?

Source: Ed Hawkins

Source: Ed Hawkins

Tom Karl, DirectorNOAA NCDC

NOAA finds globalwarming pausedidn’t happen; hiatus disappears with new analysis

6/4/15

Implications for the future: I. Consensus IPCC view

• The ‘pause’ is an artifact; or it will end soon, with the next El Nino

IPCC AR5 Ch 11

Implications for the future: II. View emphasizing natural variability

• The ‘pause’ will continue at least another decade (into the 2030’s?)

• Climate models are too sensitive to human forcing; 21st century warming will be on the low end of IPCC projections (or even below)

• Solar variations & volcanoes: wild card. Some are predicting solar cooling in the near term

• Can’t rule out unforeseen surprises

Why do scientists disagree?

• Insufficient & inadequate observational evidence• Disagreement about the value of different classes

of evidence (e.g. global climate models)• Disagreement about the appropriate logical

framework for linking and assessing the evidence• Assessments of areas of ambiguity & ignorance• Belief polarization as a result of politicization

of the science

Uncertainty • Doubt • Ignorance

Is climate change ‘dangerous’?

UNFCCC: “stabilization of greenhouse gas concentrations in the atmosphere to prevent dangerous anthropogenic interference with the climate system.”

What is ‘dangerous’ climate change?

•Extreme weather events•Climate ‘tipping points’•2oC (or 1.5oC) warming•“fat tail” arguments

Climate Sensitivity:lopping off the fat tail

IPCC AR4(2007)

IPCC AR5(2013)

Nic Lewis(2015)

How should we respond, given the uncertainty?

• There is increasing evidence that the threat from global warming is overstated

• However, if the threat is not overstated, there are major shortfalls in current and proposed solutions.

Wicked mess

We’ve oversimplified both the climate change problem and its solutions:

•undercuts the political process and dialog necessary for real solutions in a highly complex world

•torques scientific research through politicization and funding priorities

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Climate Etc. provides a forum for technical experts and the interested public to engage in a discussion on topics related to climate science, its impacts and policy options.

Twitter: @curryja