One thing is clear; the climate crisis is real, human burning of fossil fuel is by far the major driver, and we are feeling the predicted effects right now. OK, that was three things. The truth of this cleanly divides scientists from deniers.

What is less clear, maybe not even clear at all, are the implications of what we know to be true. How long do we have to fix this crisis? Is it already too late? Where precisely are those “tipping points” that begin the cascade of effects that are out of human ability to stop or control?

Scientists around the world are working to understand these questions and find answers that will inform policy in the hope that policy makers will listen. Though they all agree that a train wreck is coming if we do nothing now, there is disagreement around the urgency of the crisis.

 I often cite to scientific studies in this column. I sometimes receive feedback that the studies I refer to either overstate or understate the judgment of the scientific community. Some say things are worse than we thought, that past predictions of looming disaster way undershot the mark, and are now being revised to reflect greater urgency. Others say past studies left out uncertainties that could have a major impact on the urgency for action, such as not factoring in greenhouse gases released from warming permafrost that contains twice as much carbon as is currently in the atmosphere.

Other commenters argue in the opposite direction, in one case pointing out evidence that studies based on computer models tend to exaggerate the rate of warming and things are not as bad as some say.

Adding to the chorus of confusion (a normal part of the process of scientific inquiry) many studies address only a piece of the climate issue, leaving readers to fit that piece into the large puzzle that is, looked at from afar, the climate crisis. One such was recently published in the journal Nature and reported in the New York Times titled “Studies say Atlantic’s circulation of warm water is slowing.” Not at all an alarmist title, and only supported by less than 10 column inches of text. Couldn’t be too important, and most readers would pass over it in favor of the latest scandal coming out of Washington.

So, how to judge the content of this column? Bland title, short reporting, from the highly respected journal Nature known for its extensive peer review process, throwing around big terms like “the Atlantic meridional overturning circulation,” and a quote from a scientist at the Potsdam Institute for Climate Impact Research in Germany. Seems plenty credible, right?

Quick sidebar: Our own local author, Kim Stanley Robinson, beat the scientists to the punch with his more than 1,500 word trilogy begun in 2004, (“Forty Signs of Rain,” “Fifty Degrees Below,” and “Sixty Days and Counting”). The novel was seen by some as science fiction; but the future he wrote about, including the massive cold winters in the Northeast and the effect of colder winters on Western Europe is what reporters report on in today’s news.

I make this digression to make a point. What was seen as speculative, or even as science fiction a mere 14 years ago, is science fact today. This seems to be a repeating pattern: an alarming number of new studies find the climate crisis overtaking us faster than old studies predicted.

It’s honestly very difficult for a citizen scientist to sort all this out: the cacophony of predictions all under the umbrella of agreement that the climate crisis is real. It’s an argument among scientists, each pointing to substantial data that supports their point of view. The truth we are left with is there is no 100 percent consensus on the path forward and whether that path is mostly flat and fun to walk on or steep, arduous, dangerous and, most of all calls for urgent action now?

The key for me is, of course, to try to sift out the best science, but do so with the understanding that no one, not those who say we have loads of time to get this climate crisis under control nor those who assert that the genie may already be out of the bottle and we’d best get about the task of figuring out how to adapt to a dramatically different future, know exactly when we cross tipping points. This is important. A tipping point is when a phenomenon, let’s say melting of the permafrost, creates a feedback loop: temperature increases and permafrost melts, spewing CO2 into the atmosphere, causing further temperature increases, which melts more permafrost, again increasing temperatures, and so on, always accelerating the melting process.

A tipping point is when nature and physics take over and we are no longer in the driver’s seat. No matter what we do, perhaps short of figuring out how to quickly remove massive amounts of carbon dioxide from the atmosphere, ice will melt, oceans will rise, yadayada yada. We have all heard the litany of adverse effects.

So take my columns with a grain of sand — understanding that the beach may soon be swept away from beneath our feet.

— John Mott-Smith is a resident of Davis. This column appears the first and third Wednesday of each month. Please send comments to johnmottsmith@comcast.net.

Crossposted from the Davis Enterprise

 Published online April 16, 2018
Printed April 20, 2018 edition page A6