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This time it's different

18 Nov 2020 | News Roundup

Two professors of biology warn on The Conversation that we might be going to die because the Guardian warns that “Arctic methane deposits ‘starting to release’, scientists say”. (Wait, what happened to the bugs that were going to eat the methane?) As we’ve noted in the past, one of the newer scary climate stories is that vast reserves of frozen methane hydrate or “fiery ice” deep beneath the seas could be thawing and, if so, we will get the long-awaited runaway greenhouse effect because, as the Guardian puts it, “Methane has a warming effect 80 times stronger than carbon dioxide over 20 years”, and there’s a lot of it. But this story has the same problem all the runaway stories have: If such a process could easily and lethally be triggered now, why didn’t it happen when the Arctic was warmer than it is today over thousands of years quite recently? Or the time before that? Or the time before that?

The Conversation piece applies a veneer of caution about the research not having been peer-reviewed, as if that guaranteed anything. But then it peels back the veneer to depict an accelerating catastrophe just waiting to happen. “Methane is not as common as carbon dioxide, but it also contains carbon and is a potent greenhouse gas. Many people have heard of methane being stored in Arctic permafrost, but few realise that there are also massive and much larger deposits of the gas locked beneath the seabed. Although seabed greenhouse gas thawing has been foreseen – and feared – for some time, it was only suspected to become a serious problem by the middle of this century. If it now seems to be melting much earlier, its a signal that human indifference to the environment, and release of fossil fuel carbon, is now being effectively amplified by the disintegration of our own planet’s geological balance. To put this into perspective, there is perhaps 20 times more carbon stored in these natural underground reserves than in the entire biomass of Earth combined – that is, all plants, animals and microbes. Clearly, there is at least the potential for greenhouse gas to be released from these deposits on a significant scale.”

Well, yes, it seems to be a signal perhaps of the potential for significance. But as to the “clearly”, let’s take another look at this common notion of Earth’s natural “balance” disintegrating on the slightest provocation as various warming processes amplify one another. Is it reasonable to think of the climate in such terms in light of the evidence? By evidence we don’t mean computer projection (as the Guardian concedes “With the Arctic temperature now rising more than twice as fast as the global average, the question of when – or even whether – they will be released into the atmosphere has been a matter of considerable uncertainty in climate computer models”) or speculation about the meaning of some bubbles. We mean solid evidence of the factual sort.

We actually have a lot more such evidence about climate change and GHGs than you might suppose. The problem is, it’s not where the alarmists think. It’s not inside computer models that pile a Pelion of assumption on an Ossa of incomplete evidence and only reach the Olympian heights of disaster because they’re programmed to do so in the face of almost any inputs. It’s in the past.

To be sure, it’s not as solid as we might like. We don’t know as much as we would like to about the past history of the Earth’s climate, and much of what we hope we know is of course based on reconstructions not observations. Nobody took the temperature in the Eemian using a stone thermometer. And even Stonehenge was, we think, a calendar not a barometer.

So we use various proxies to determine temperature and atmospheric CO2 and so on, and the further back you go the more speculative it all becomes. But for all that uncertainty, there are a few things that seem fairly clear. And one of them is that temperature has fluctuated in the past. A lot.

At this point some people will try to wave us off, saying yeah, sure, it fluctuated in the past. But it doesn’t matter because it’s changing much faster now than it ever did before. Which is a dubious assertion for another day (but for instance Google “Younger Dryas”) because it has no relevance to the point under consideration, which is the question of runaway amplifications triggered by relatively modest warmings.

On that issue, what matters is that we know the Earth has been considerably warmer than it is now for most of its history. Certainly before the Pleistocene began about 2.5 million years ago there had not been significant glaciation for over a quarter of a billion years. Atmospheric CO2 was higher than it is now and so was temperature. For that matter it seems quite clear that it has often been warmer even during the Pleistocene than it is today, in past interglacials and even within the current Holocene one during the Roman Warm Period and probably the Medieval Warm Period too and certainly the Holocene Climatic Optimum. And yet, and here we reach the key point, we did not see runaway warming at those times.

The Conversation asserts that “Methane entrapped in their icy jail cells of hydrates underground ought to stay there for millions of years, accumulating over the aeons.” But then why “ought” it to be released today? After all, those millions of years were warmer than today, so why would today’s warming produce an effect past warmings did not? It’s astounding the extent to which, as geologist Ian Plimer once put it, “the one thing that we miss out on in looking at climate change is the past”.

If the “fiery ice” is going to melt, directly because of temperature or due to the various ingenious mechanisms discussed in the Guardian and Conversation pieces, and in doing so reinforce the warming that melted it so that we reach one of those famous tipping points, why did it not do so around the time Caesar was getting the business on the Ides of March? Or during the Holocene Climatic Optimum some 7,000 years ago, when nobody denies that it was warmer than the IPCC fears it might get by 2100? Why didn’t the Eemian interglacial, known to have been warmer than the Holocene despite lower CO2 levels, release the dreaded methane and fail to end because of the famous “greenhouse effect”? For that matter, why didn’t the warmth of the Pliocene prevent the Pleistocene from happening at all? Or the warmth of the Eocene?

A logical response would be that climate is complicated and various factors including the famous Milankovitch Cycles led to the Pleistocene glaciations. Which is fair enough. But surely incompatible with the simple linear model where any significant warming above the historically chilly 1970s must launch a host of reinforcing processes creating a “greenhouse effect” where the planet gets hotter and hotter and “Tibet will become like Afghanistan” in the words of that noted climate scientist the Dalai Lama.

If Tibet were going to turn inexorably into Afghanistan, the methane were going to melt and the planet were going to become uninhabitable due to warming, it would have happened in a previous warming. Since it didn’t, there must be other more complex and cross-cutting processes at play.

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