I’ve been butting heads with some folk about AGW for a bit now. It’s causes a few posts here, and this is another. This one came about because of the new “great proof” being kicked about: Half-precessional dynamics of monsoon rainfall near the East African Equator by Dirk Verschuren1, Jaap S. Sinninghe Damsté2,3, Jasper Moernaut4, Iris Kristen5, Maarten Blaauw6, Maureen Fagot1, Gerald H. Haug7,8 & CHALLACEA project members (link).
Put VERY simply, the article incidentally demonstrates that the glacier on Mount Kilimanjaro shrinks and grows in a cycle that’s tied to wet and dry periods. The crowds are going nuts saying this proves it’s not shrinking from global warming.
Allow me to do an extended boot to the head. Let me start with the show-stopper — the same report says we’re presently in a wet period. By the report, then, the glacier should not be shrinking.
Look, the shrinking glaciers are due to output exceeding input. Melting and sublimation (hereinafter M&S) are outpacing precipitation.
There is some work that says the rate of M&S is still about the same and the cause is reduced precipitation. I’m willing to accept that but it brings us back to the core question: what is the cause? What is causing the reduced precipitation? And with that we enter the next boot.
In the Kilimanjaro region there’s been a lot of forest harvesting for a long time. There’ve also been quite a few weather stations present for a long time as well. There’s a decent case – strong enough to put it down for consideration – that the reduced precip is related to / caused by the deforestation.
Boot one: What do you think “anthropo” means, anyway?
Boot two: the same stations that record reduced precip also record slightly higher temperatures. If you trust the data from one instrument in the station, why don’t you trust the other in the same station? Rejecting a datapoint because it disagrees with your theories is what you accuse the AGW people of doing.
More boots exist, of course. There are tropical glaciers that are NOT near heavily deforested areas. They are also shrinking due to a combination of (possible) increased M&S and (measured in some areas) decreased precipitation. Since deforestation can’t be the cause in these regions, what is? And why is the rate of shrinkage notionally similar to that of the deforestation glaciers?
I have a simple demand. Theories get tested. The majority of non-scientific anti-AGW demand the AGW be tested (and tested with hands tied behind the back, often enough), but they want to make blind acceptance of NGW and non-GW theories. That’s not acceptable. Change is happening. Propose a theory to explain it that can be tested for refutability. “It just is” or “since the opposing theory is found to have errors we can just accept ours” are unacceptable.
FWIW, in the climatological science field, NGW theories do get set up for testing. There’s plenty of data from a wide range of subfields done by a very large number of people that has confirmed we’ve been warming for the past 150 years or so — arguing we’re not is simple denial. I have grouped the two together in this post but that’s highly unfair. GW Denialists slice and dice the data to meet their opinions. For example, they’ll tell you we’ve been generally warming since the end of the last glacial period – never mind the peak of the Holocene Climatic Optimum about 8-9 thousand years ago after which we generally declined in temperature. Yes, it’s similar to saying at 3 pm. that measured from dawn, on average the sun’s been climbing.
Glaciers around the world are shrinking. GWDs haven’t provided any testable theories. NGW and AGW proponents have theories. Neither groups’ theories are perfect fits, but from my reading the AGW fits better.