Scientific case for warming is not a popularity contest

To me, many of the recent letters to A.M. Costa Rica are indicative of:

[a] right wing political and/or religious conviction rather than thoughtful analysis of valid science;

[b] incognizant, or ignorant, or just resistant to the hundreds of verifiable indicators of global climate change;

[c] wishful thinking of the world as it SHOULD be.

If my opinion is offensive to you, re-read “The Emperor’s New Clothes.”

There is absolutely no question of global warming currently taking place. It began coincident with the advent of high-carbon coal and petroleum in the period called the Industrial Revolution around 1800. Because coal and oil represent billions of tons of fossilized plant and animal life, it is not surprising that all that carbon, released into the atmosphere by burning, is raising carbon dioxide levels.

The CO2 levels are 390+ ppm now, as opposed to 270 ppm in 1800. In the 1,000 years before that, the amount varied ONLY from 270 to 290 ppm. This is indisputable, based on analysis of air bubbles in Greenland ice cores. The best scenarios suggest that in the lifetime of our grandchildren, the CO2 level will rise to 500 ppm [if we’re lucky, that is – could go higher if our heads remain in the sand]. There is only minor disagreement as to whether humans are the cause of this 40+ percent increase in 2+ centuries.

Sure, the earth has been much warmer in the past — the “Great Eocene Warming” for example. But it took several million years to get there. What are the planetary consequences when a comparable warming takes place in 1/10,000th of that time? The kind and impact of those consequences are where much of the controversy comes in. In the global carbon cycle, the rising level of atmospheric CO2 and its human origins are about the only two things that are known with a high degree of certainty.

And the rate of injection of CO2 into the atmosphere is increasing – it was increasing at ~1 percent per year in 1970-90. In recent years it is increasing at ~2.5 percent per year. The total CO2 increase in just the last 11 years is MORE THAN double that for the entire century of 1800 to 1900. Indisputable.

“97 percent of climatologists say global warming is occurring and caused by humans” The reality of global change is not related to voting, nor is it a popularity contest. Climatologists and earth and ocean scientists are following this planetary change [I am one] and [though scientists, as a whole, are doing poorly at communicating their science to the general pubic] we follow with considerable alarm. The climate change deniers talk of scientific conspiracies to promote warming fear to increase research, but this is paranoid nonsense.

To me, there are greater problems than CO2, though CO2 plays a role. The present increase in temperature is causing increased thawing of millions of square miles of frozen tundra and permafrost areas across the high latitudes, especially Canada and Siberia. This is allowing microbial metabolism to degrade thousands of years of frozen vegetation, resulting in the release of methane. Why important? Methane is 26 times more effective as a greenhouse gas than CO2. Figure it out. Also, we see some cognoscenti saying “not to worry, the oceans will take up excess CO2.”

Well, here’s the problem: [1] as the oceans warm (currently in progress), CO2 is less soluble, so less will be taken up as things warm up further; [2] CO2 in water forms carbonic acid, lowering the pH so that things like corals, shellfish and many other critters will struggle to survive or die off altogether. Not to mention that sea levels will surely rise higher [as they are now unequivocally doing] simply because warmer water is less dense and will expand. To where will it expand? Why, over the shore of course! The only places where this will not happen is due to something called isostatic rebound [can’t go into it here].

Water vapor? Sure it’s a greenhouse gas — and far exceeds CO2 in amount and impact. But the additional warming due to our CO2 input will increase global evaporation from the oceans (71 percent of the earth’s surface), thus increasing water vapor, thus leading to…..more warming — in a situation of positive feedback loops. Some modelers tell us we are closely approaching a tipping point: things will get much worse no matter what we choose to do, if a critical threshold is reached. I don’t always trust modelers, but it’s a scenario worth examining closely.

Finally in my rant, people in the northern U.S. say that this past winter is proof that global warming is a hoax. Politicians are particularly susceptible to this absurdity. Somehow, people have trouble distinguishing between weather and climate, and in distinguishing between their hometown [or country] and the rest of the world. Most climate models [some are better than others] predict that changes in temperature and precipitation will be highly uneven around the planet.

Recent events suggest there really is something to this: the crippling drought in Russia resulting in wheat crop failure; the droughts and fires in Australia, followed by the worst floods in centuries — there are dozens of other examples, many more than just coincidence or weather variations would allow. As these events increase in frequency in Third World countries, you can bet that political and social unrest will follow — one reason why the U.S. State Department and the Pentagon have task forces trying to figure out what will happen in a warmer world. Poorer countries in Africa and south Asia are particularly vulnerable.

No one will change their mind about climate change after reading anything in A.M. Costa Rica — this is not a discussion group for the details of the topic. But it makes my head hurt to read letters by people who clearly have no familiarity with the possible consequences to our planet of changes in ENSO, NAO, ITCZ, PDO, and other global phenomena defined by their acronyms, as a result of climate modification. As I tell my students in my Global Change in the Marine Environment class, in Pogo’s words, “We have met the enemy and he is us”.

(I see Instituto Meteorológico Nacional is predicting a much hotter March and April for Costa Rica. Hmmmm. I’m thinking northward shift of Intertropical Convergence Zone, especially. if the green season comes early.)

Paul E. Hargraves
Emeritus professor of oceanography, University of Rhode Island,
Affiliate professor, Harbor Branch Ocean Institute, Florida Atlantic University
and research associate, Smithsonian Marine Station.

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