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Gavin SchmidtNASA Goddard Institute for Space Studies

New York

Pace U., Jun 2012

Communicating Climate Change:Impacts and the public discourse

Monday, July 30, 2012

Politicized ScienceScience gets politicized when scientific results appear to impact vested political, ethical or moral interests

New results are only seen in the public realm to the extent that they project onto the political/ethical/moral question

'Scientized'* PoliticsPolitics get scientized when advocates appear to debate the science in order to avoid debating the values that underly their positions (*coined by Dan Sarewitz)

Nothing to do with real scientific debate'Science-iness' is used to make a case, not find the truthCherry-picking, strawmen, red herrings common


Consequences?

Good: Nature or Science! Media coverage! Bad: DistortionPoliticsMuch more public scrutinyInaccuracy, Sensationalism, over-interpretation commonPublic understanding decreases, trust in science erodesContinual 'debate' about irrelevancies hinders serious discussion


Just the facts, ma'am...

… are not enoughMonday, July 30, 2012

ShishmarefArctic sea icePine bark beetlesSouthwestern drought...


What's hard to explain?

The nature of science: People often imagine/expect scientists to have all the answers Not comfortable with provisional nature of science

Colloquial vs. scientific ‘proof’ What is the difference between a theory or a law or a hypothesisWhat a 'model' is...


Examples of when things go wrong


Methane from plants – Keppler et al

Previous week's news context:

Whether reforestation should get credits under the Kyoto Protocol

From the Press Release:

“plants themselves produce methane and emit it directly into the atmosphere”

“This discovery is important .... for understanding the connection between global warming and increased greenhouse gas production.”

“Methane is the greenhouse gas which has ... the second greatest effect on climate, after carbon dioxide. .... Methane in the atmosphere in fact is largely of biogenic origin.”


Unsurprising results

Second press release put out a week later to correct 'misconceptions'


Sea Level Rise by 2100?


Future climate impacts?

Temperature rises are robust predictions......but not everything else is


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Projection uncertainty

1) Scenario uncertainty (technology, economy etc)2) Initial condition uncertainty (weather 'noise')3) Model uncertainty

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3

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Global Temperature Local Temperature

Hawkins and Sutton (2009)Monday, July 30, 2012

How robust are rainfall projections?

Stippling denotes 80% of models agree on sign (above) or majority of models suggest change is significant (right).


Asking the right questions


Different issues are connected!

Air pollution and climateWater resources and climateAcid rainOcean acidification

Policies for one issue have impacts on other issuesPolicy-relevant science is increasingly policy-basedi.e. UNEP report on Black Carbon and Tropospheric Ozone


Getting projected ducks in a row...

Does a result make theoretical sense?

Does it come from multiple models?Is there some

observational support?

Does the size of effect line up?


How can we say something useful?

Use projections to assess possible vulnerabilities(No absolute predictions)

Use global mean temperature change as a 'proxy'(i.e. impact associated with x ºC rise, not what will happen in 2050)

Use full spread of model results as a guide (until there are reasons to discount outliers)

Use finer-grained local knowledge(not necessarily reproduced in global models)

Must not neglect other human influences, adaptation measures, uncertainties


A relevant quote...

Prediction is difficult, particularly of the future. -Niels Bohr

In all good bookstores!

http://www.realclimate.org


There is much work to do...


communicating climate change: impacts and the public … › ... › files › pecc ›...

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