heywood on 15/8/2012 at 08:23

---

On the contrary, the scientific method tells me not to assume anything and only accept a hypothesis when there is sufficient weight of evidence in favor of it over alternative hypotheses.

Methane clathrate is looking questionable as a primary cause. It was suggested in the hope that it could explain the observed rapid increase in Carbon-12 at the end of the Permian. The problem is that later measurements found the C-12 spike wasn't an isolated event. The C-12/C-13 isotope ratio continued going through large positive and negative excursions throughout the early Triassic and that isn't consistent with a methane clathrate explanation.

We haven't put together all the pieces of the P-T extinction puzzle yet. We have evidence of a rapid mass extinction which coincides with a major disruption in the carbon cycle, major global warming, a continent-sized basalt flood eruption, oxygen depletion, H2S release, sea level change, fossil irregularities & deformities right before the extinction, and probably other stuff I'm not aware of. That was followed by ~5 million years of carbon cycle instability until it suddenly went normal again and life recovered. There are hypotheses about what caused what, but no coherent theory that puts it all together. Methane hydrate gasification might be a major piece of the puzzle, or a minor piece, or irrelevant.

My point was that I'd like to see less doomsday conjecture and more boring old science, especially among scientists in the public eye (e.g. Hansen) who should be educating the public on the science instead of evangelizing.





I don't mean we try to avoid setting them off, I mean we try to avoid playing into their hands.

faetal on 15/8/2012 at 08:51

---

I'm a research scientist by profession - I get how it works. I've done some more reading and yes you are right, it is looking like clathrates are out for the P-T extinction in favour of sheet basalt followed by coal fires followed by H2S excretion by anaerobic bacteria.

My knowledge was a few years out of date, but then, I'm a toxicologist, not a climate scientist. I wasn't going against the scientific method by assuming, I was just going by 6 year old information, which is an easy mistake to make, particularly outside the boundaries of one's field.

The point is that regardless of gas hydrates, we are looking at reduced living conditions because of the rate of change. The speed of these changes are occurring at an unprecedented rate. The coal fires thought to be part of the P-T extinction were warming by releasing CO2 into the atmosphere. I don't think people fully appreciate just how much we are changing the atmosphere by rampantly burning trillions of tonnes of sequestered carbon.

Change of the climate has only ever been catastrophic when it has happened too fast for effective adaptation. The trouble with what is happening at the moment is change which is too fast for evolution to adapt to, which means that as climates get more different from their usual baselines, fragile species will decline and opportunistic or "weedy" species will thrive. This will drastically alter food webs in ways we can't predict. Doomsday scenarios are not really the first issue we should be worried about. If the global food supply is disrupted, then the social effects and geopolitical outcomes are likely to be the first set of natural disasters. Wars for oil are all fairly speculative and based around a less pressing imperative than the need to eat. If food ever becomes the focus of conflict, it will likely be very bloody. Various political affiliates can equivocate on the need for domestic oil - my guess is we won't see that for food.

One thing which is a genuine concern in terms of biological outcomes is that insects and plants react very differently to climate change. Plants, being sedentary react to things like moisture, temperature and chemical signals either airborne or in substrate. Insects are affected by various other environmental factors related to where they nest, where they feed. So if their life cycles are altered in response to climate change, it is unlikely that all of them will change at the same rate, which risks the de-synchronisation of plants and their pollinators. If enough species are affected (and evidence is already showing that some are), then we could see catastrophic consequences in a very small time frame.

We need to act as soon as possible, least of all because CO2 has a fair old half-life in the atmosphere, so even when we stop, there will be a lag. Even if we leave out gas hydrates, there are plenty of positive feedback mechanisms, including ice albedo loss and tundra permafrost thaw which will kick the rate up and reduce our chances of being able to do anything.

faetal on 15/8/2012 at 10:28

---

Also, due to the general public not understanding how modelling works, any time the models turn out to be incorrect, people assume that everything's fine, global warming isn't happening and scientists don't know anything because they don't know everything etc...

Models can do some decent extrapolation from trends, but they can not predict the future. However, we can reasonably expect the future to contain a decent chance of "hard times ahead", we're just not sure of the magnitude, or the extent to which we can prevent it, or how fast and how far we need to go to do so.

As far as right wing libertarians are concerned though, even if the biosphere does start going to hell,it's nothing to do with humans and we should just burn more oil to show how unphased we are about it all.

faetal on 15/8/2012 at 10:53

---

What is simulation if not heuristics driven extrapolation?

Perhaps I am being too loose with words.

faetal on 15/8/2012 at 11:03

---

Not literally, no. Models do rely on coefficients derived from historical data though, so I guess it can be seen as analogous to extrapolation, but we're splitting hairs a bit. I think we both get what I meant, broadly speaking.