By George Harvey
James Hansen is the legendary NASA climate scientist whose testimony before the United States Congress first made many people aware of climate change in 1988. By then, he had already identified one culprit in the process, the greenhouse gases in the atmosphere that trap the sun’s energy, warming our planet. Since that time, he has engaged in a series of studies, both for NASA and, most recently, as a climate activist. It is worth noting that he retired from NASA because, he said, “as a government employee, you can’t testify against the government.”
Most recently, Hansen and sixteen other top-rated scientists jointly published a paper on melting polar ice. They describe a feedback loop, in which the colder fresh water melting from polar ice pushes warmer salt water against the ice, causing it to melt faster.
The paper was published through an unusual mechanism, because its authors wanted to make it available to governments at the United Nations Climate Change Conference (COP 21) in Paris, which begins on November 30, 2015. Instead of having the paper peer-reviewed and published, it was made available online, to be reviewed by scientists. At the same time, anyone who wishes can follow the whole process at home. It can be viewed at bit.ly/Hansen-2015-climate-paper as a 66-page pdf file.
The paper was intentionally exposed to extremely close scrutiny. We can bet that just about everyone who has some reason to want to show climate change is a hoax will weigh in. The peer review process is open to qualified scientists, but there will no doubt be a lot of commentary by people outside the scientific disciplines involved at various venues on the internet.
The report, “Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2° C global warming is highly dangerous,” is alarming. Assuming it is correct, coastal areas are in worse trouble than we had thought. It says the ocean rises that predictions say could to swamp coastal cities around the world will not be prevented by holding temperature rises to 2° C. The feedback loop may already be underway, and it would cause seas to rise by a number of meters over the coming decades.
Specifically, the paper says, “If the ocean continues to accumulate heat and increase melting of marine-terminating ice shelves of Antarctica and Greenland, a point will be reached at which it is impossible to avoid large scale ice sheet disintegration with sea level rise of at least several meters.”
We might pause here and consider what a rise of several meters would look like. Three meters is about ten feet. That might not sound like much, but it would inundate many major cities around the world. Storms, which are also projected to be much worse, would cause the high water marks to be meters above that. In a place like New York or Boston, this could make maintaining the subway infrastructure untenable. It would make homes all along nearly all coasts of the world uninhabitable, and with them, destroy highways, chemical plants, nuclear power plants, and so on.
Of course, if we fail to limit greenhouse gas emissions, and the temperature rises by 3° C or more, things will be much worse. Scientists, looking at the promises countries make as they plan for COP 21, say they expect the limited actions described will not be enough to prevent a 3° C rise.
We must do better, and that is why Hansen and is colleagues are publishing their paper for all to see, as they are.