Climate of Risk and Uncertainty contacted me asking what I thought about Bret Stephens’ first column in the New York Times. Here, is a slightly edited version of my response.

Bret Stephens’ opinion piece, titled “Climate of Complete Certainty”, is attacking a straw man. No working scientist claims 100% certainty about anything.

Science is the process of falsification. Hypotheses that have withstood a large number of attempts at falsification, and that are consistent with a large body of established theory that has also resisted falsification, are widely regarded as true (e.g., the Earth is approximately spherical). Many hypotheses of modern climate science fall into this category.

It is also true that some ‘environmentalists’ go far beyond the science in making claims, but that is not cause to denigrate the science.

Bret Stephens writes of ‘sophisticated but fallible models’ as if ‘sophisticated but fallible’ gives one license to ignore their predictions. A wide array of models of different types and levels of complexity predict substantial warming to be a consequence of continued dependence on using the sky as a waste dump for our CO2 pollution. It doesn’t take much scientific knowledge to understand that the end consequence of this process involves approximately 200 feet of sea-level rise. We already see the coral reefs disappearinga predicted consequence of our CO2 emissions. How much more do we need to lose before recognizing that our ‘sophisticated but fallible models’ are the best basis for policy that we have?

Yes, we should take uncertainty into account when developing policy, but we should recognize that those ‘sophisticated but fallible models’ are as likely to underpredict as overpredict the potential consequences of our greenhouse gas emissions.

Stephens would have been on more solid ground if he would have confined his comments to uncertainty in the ability of human systems to adapt to the relatively more certain projections of changes in the physical climate system. Will we be able to give up low-lying countries and the major coastal cities of the world (New York, London, Tokyo) without much of a transition cost? Will people in India and the Sahel be able to migrate or air-condition their way out of the harsh conditions projected for those areas? These are open questions about which well-informed people can disagree.

It is dangerous to act as if uncertainty in climate model projects justifies inaction. Uncertainty equals risk. One way to reduce uncertainty is to increase the amount and quality of climate science being conducted. Another and more important way of reducing uncertainty is to reduce human influence on the climate system. This requires a major transformation of our energy system to one that does not rely on the atmosphere as a waste dump for our CO2 pollution.

Climate science does not offer complete certainty about the future. Instead, it points to substantial risks and ways to avoid that risk.

Straw-man attacks on climate scientists do not productively advance the discussion.

For reference: My first reaction to the announcement of the The New York Times decision to hire Bret Stephens.


Scientific reproducibility, communication of uncertainty, and the US House of Representatives

Bobby Magill of Climate Central sent me an email asking me to comment on several bills recently passed by the US House of Representatives. Specifically, he asked me to comment on bills rescentely
– H.Res.229. … would require EPA actions to be based on science that is “transparent” and “reproducible.”
– HR 1431, …would prevent the EPA Science Advisory Board from communicating uncertainties.
My email comments to Bobby are below: His story is here:

All of the climate science, and related environmental science, that I read in the peer-reviewed literature is in-principle reproducible. The reason it is not in fact reproducible is that the Federal funding agencies rarely provide resources to redo work that someone else has already done.

If our Congressional and Senate representatives really want to see us do science that is reproducible in a practical sense, they should double or triple research budgets so that scientists can afford to do the same thing two or three times.

In practice, once someone has done something to the satisfaction of thee peer-review system and the broader scientific community, people move on to try to make new discoveries.

You can be sure that scientists love nothing more than showing that our colleagues are wrong. If something gets published that smells fishy, that’s when scientists are motivated to redo the study and show that they are wrong. This, for example, famously happened with the cold fusion studies that were published some years ago.

Why would a working scientist with limited funds want to allocate scarce resources to testing something the scientific community already thinks it knows rather than exploring something new? To have enough resources to want to spend it treading over old ground would require a substantial increase in science funding.

Science is all about communicating uncertainty. Science doesn’t prove things. Science works by trying to disprove things. The harder people work to disprove a statement, and the more they fail at disproving it, the more people come to believe the statement is true. Science is about expanding the range of what we know to be false. Truth lies in the range of what we don’t know to be false — that is the uncertainty range.

People who don’t want scientists to communicate the uncertainty range are people who don’t understand what science is all about.

Image from Climate Central story: Credit: C.L.Baker/flickr