Some Remarks on Global Warming

I appreciate the balancing act Dr. Mohler is doing on global warming. He says there is middle ground, and acknowledges Christians’ dual responsibilities of dominion and stewardship. That’s good, as far as it goes. But he makes several points that lean against taking global warming seriously and concludes with skepticism about our ability to combat it. I respond:

Dr. Mohler seems to believe that global warming claims require a very long record of weather data, and thus rely very heavily on “retroactively created” weather conditions from before measurements were made, and such reconstructions are not “beyond dispute”. It’s true that a great deal of effort has gone into reconstructing past climate conditions using many different sources of evidence, from tree rings to ice cores. But these efforts are by no means the only support for the theory. The measurements we do have, going back decades, from all over the globe, are used to test computer models of the oceans and atmosphere. These models incorporate everything we know about the physics of the air and oceans. The better the models get, the more accurately they reproduce the recorded observations – the patterns of changes in the winds and currents and temperatures over time from all over the globe. And these models are only able to fit the actual patterns observed when human generated greenhouse gases are included in the models. You can see a graph here, comparing the global temperature record with model simulations that include greenhouse gases emitted by humans and ones that don’t. (At least you can today. There’s no telling what the EPA under Pruitt will be able to show in the future.)

Dr. Mohler also mentioned an “unexpected pause” in global warming which was “inexplicable”. He took this to be “a humbling reminder, of how little we actually know and how little perhaps we can actually do about the larger question of the climate.” This is a very unfortunate lesson to take away. And as a matter of fact, Dr. Mohler’s information is outdated. More recent work has shown that the ‘pause’ or ‘hiatus’ never happened. It was an artifact of a shift in the source of measurements from ocean temperatures taken in ships to ones taken by buoys. The buoy measurements were colder than those made in ships’ engine rooms, so a shift to reliance on buoys pushed the data lower over time. When this bias was corrected for, the hiatus went away.  2016 was the third year in a row to set a new record for global average surface temperatures.

Dr. Mohler says the controversy is not only over facts, but worldviews. What seems to trouble him most about environmentalists is their past advocacy of population control:

“The existence of human beings, certainly of more human beings, on the planet is seen to be a problem. Now, again, that is a direct refutation of the Christian biblical worldview that understands that every single human being is an image bearer of God and reminds us that in Genesis 1, God gave to the human creatures made in his image, male and female, a dominion to go forth and to multiply and to fill the earth.”

I don’t think there is any conflict between concern about population growth and a view of human beings as image bearers. If God commanded us to “Be fruitful and increase in number and fill the earth”, that implies that the earth can be filled. Surely once it is filled, the command to increase in number has been fulfilled. God did not add, “and once it is filled, go on increasing until there is not place to stand nor bread to eat.” At some point, there will be enough people, and the earth will be filled. How many more doublings of population size must occur before we decide that time has come? However many it is, it will be a small number. – But that is a separate question from what we must do in the near future to really stall global warming.

One more point. Dr. Mohler affirms that “the market is likely to resolve these issues.” Markets are powerful shapers of human activity, and there are market forces driving a move to natural gas and renewable energy. But will they be enough to do the job? That is a question for people who actually do the math. And we should remember that markets are only “wise” if all the costs are priced into the market. If there is a price for pollution, the market will find a way not to pollute. But if there isn’t, polluting ways will continue, profiting some, while possibly imposing very great costs on us all. A carbon tax is one way to ensure that the market works the way it should – for the greater good.