Sunday, March 29, 2015
I occasionally make reference to my other life in this sailing blog - my part-time work as a marine biologist pays for all this nautical carrying on of ours. Most of my work has to do with the ways that "external" factors, like commercial fishing and climate variability/climate change, affect the suite of species living on Alaska's continental shelves.
So, as a part of this other life of mine, I've got a working knowledge of climate science, and I read some of the torrent of new climate papers that are forever appearing.
This one really caught my eye.
The plot above is the rate of surface temperature change for the globe since 1900.
Almost everything has gotten warmer, of course. Take a look at poor Alaska.
But then there are those two big areas that have cooled over the last 100+ years.
The cooling spot in central North Africa is apparently an artefact of poor data quality. But the cooling in the North Atlantic is, according to the conclusions of a recent paper in Nature Climate Change, the result of a weakening Gulf Stream.
The Gulf Stream is just one part of a global system of surface and deep-water ocean currents that plays a vital role in distributing heat around the Earth to give us the climate system we know.
Human society evolved during a period of unusual climate stability. But before the appearance of modern humans - on the order of hundreds of thousands of years ago, if I remember my class in Geological Oceanography at all accurately - there are incredibly rapid changes in the climate record, when average global temperature apparently changed by several degrees within a decade or so.
Since the 1980s/1990s, scientists have recognized that sudden change to the Gulf Stream and other global currents could be a mechanism that would produce such a sudden change to global climate, and have accordingly been concerned about the effects of global warming on that current system.
I've seen other studies that presented evidence that the authors thought indicated a slow-down in the global current system, but this one just seemed particularly startling - here's evidence of the Gulf Stream slowing down, in real time.
As many other people have pointed out before me, uncertainty in projections of where we're taking the climate cuts both ways.
If you're growing corn in Kansas for a living, or if you live in coastal Florida, it's looking like good odds that your kids won't end up doing what you're doing. But for the rest of us, there are all sorts of unanticipated outcomes that are associated with changes like a weakening Gulf Stream.
Addressing the causes of anthropogenic climate change will be an incredibly daunting problem in building consensus within and between countries.
Unfortunately, in both the countries in which I hold citizenship, the political right has nurtured an extensive fantasy world in which the science is not real. I suppose that the right has the natural role of supporting the status quo, and in this instance that has developed into a situation where a handful of fringe characters, largely funded by carbon polluters and parroting scientific nonsense that has been discredited by a huge body of work (see, for instance, Willie Soon), are given equal weight to the work of tens of thousands of scientists who have reached one of the strongest consensus positions that can be found anywhere in contemporary science, and done it by working in a skeptical, rigorous way.
The motives of people actively involved in science denial are likely captured by that great Upton Sinclair quote about how "It is difficult to get a man to understand something, when his salary depends upon his not understanding it".
But my heart goes out to people who have uncritically adopted a worldview that bases the denial of climate science on the most abject mix of infactual nonsense. It reminds me of the intelligent, well-meaning friends of mine whom I've heard repeating balderdash about vaccinations - smart people, often poorly educated in science, unable to correctly evaluate competing arguments.
So, in the end, I suppose this post is aimed at those people. If you have read this far, and think there is any sort of scientific controversy about the fact that human activities are massively altering global climate, know that you have been sold a very shoddy bill of goods. And I would propose that it is incumbent on all of us, if we enjoy any sort of political agency in the world, to become reasonably well-informed consumers of information on climate science, and to think long and hard about the possible motivations of people who would have you believe that the entire enterprise of climate science is some sort of idealogical exercise.
When reasonable evidence appears that people are slowing down the Gulf Stream, it's time for reasonable people to pay attention.
A longer description of the Gulf Stream study is here.