I don't much about climate change other than what I read about glaciers shrinking, snowcaps melting, aquifers drying up, yadda, yadda. I simply don't have the information to make an informed decision nor the time to delve into it but FWIW, it seems to me like we're warming up.
But for those who know, is it carbon dioxide that's the primary issue or methane or both? Because if it's carbon dioxide, we should be planting trees like all get out. And if it's methane, well that brings up a different matter related to microbial life forms. Any knowledgeable parties have the definitive answer?
Well ao, it's both, in differing amounts.... currently it's mostly CO2, but methane is starting to escape from thawing tundras in the Arctic at an alarming rate, and as it's 22 times more potent a greenhouse gas (though not as long lasting) some people are freaking out that it could become a positive feedback loop that will create a tilting point...
Worryingly, methane is also escaping from fracking sites, and they too are growing exponentially in numbers, all over the world.
BEST land-only surface temperature data (green) with linear trends applied to the timeframes 1973 to 1980, 1980 to 1988, 1988 to 1995, 1995 to 2001, 1998 to 2005, 2002 to 2010 (blue), and 1973 to 2010 (red). The final 'skeptic' frame is available here, and the 'realist' frame is available here.
A version of the Escalator using land and ocean data from NOAA NCDC is availalble here. In this version, the short-term cooling trends shown are from Jan '70 to Nov '77, Nov '77 to Nov '86, Sep '87 to Nov '96, Mar '97 to Oct '02, and Oct '02 to Dec '11 (blue) vs. the 42-year warming trend (Jan '70 to Dec '11; red) using NOAA NCDC land-ocean data. The final 'skeptic' NCDC frame is availalble here, and the realist NCDC frame here.
By weight, it's mainly CO2.
Measured by climate forcing affect it's about:
But planting trees etc is only remedial action. The root problem is moving about 8.5 gigatons/year of carbon from the geology to the biosphere, via burning fossil fuels.
Currently 4.5 gigaton/year is staying in the atmosphere while 3 gigatons/year is being dissolved into the oceans and 1 gigaton is being absorbed by forests etc. About 0.1 gigatons/year is being absorbed into the geology in sediment deposits, about matching the amount being released by volcanism.
We are seeing the first signs of dangerous climate change in the Arctic. This is our warning that humanity is facing a dire future.
The Arctic region is fast approaching a series of ‘tipping points’ that could trigger an abrupt domino effect of large-scale climate change across the entire planet. The region contains arguably the greatest concentration of potential tipping elements.
If set in motion, these can generate profound alterations which will place the Arctic not at the periphery, but at the core of the Earth system. There is evidence that these chain reactions have begun. This has major consequences not just for nature, but for the future of humankind as the changes progress.
Research shows that the Arctic is now warming at three times the global average. The loss of Arctic summer sea-ice forecast over the next four decades – if not before – is expected to have abrupt knock-on effects in northern mid-latitudes, including Beijing, Tokyo, London, Moscow, Berlin and New York. The loss of sea ice – which melted faster in summer than predicted – is linked tentatively to recent extreme cold winters in Europe.
Arctic records show unambiguously that sea ice volume has declined dramatically over the past two decades. In the next 10 years, summer sea ice could be largely confined to north of coastal Greenland and Ellesmere Island, and is likely to disappear entirely by mid-century.
Some environmental and biological elements, including weakening of the oceanic biological carbon pump and the thermohaline circulation,melting of the Greenland ice cap, thawing of Arctic permafrost and methane hydrate deposit, the decline of forest and peat fires in the boreal region, may be linked in a domino effect of tipping points that cascade rapidly once this summer sea ice is lost.
Despite this danger, semantic confusion masquerading as scientific debate – although providing excellent media fodder – had delayed an urgent need to start managing the reality of dangerous climate change in the Arctic.
And of course there are those who benefit from a warmer Arctic. A drop in Arctic ice has opened new shipping routes, expanded oil, gas, and mineral exploitation, increased military and research use, and led to new harbours, houses, roads, airports, power stations and other support facilities.
It has triggered a new gold rush to access these resources, with recent struggles by China, Brazil and India to join the Arctic Council where the split of these resources is being discussed. Not everyone is in favour of reducing the impact of warming on Arctic ice.
But all of us need to take this melting seriously. Top predators such as polar bears are declining. More methane gas is entering the atmosphere as permafrosts and submarine methane hydrates thaw. Freshwater discharge has increased 30 per cent in recent years. And the Arctic Sea is warming faster as the ice cap melts, trapping more solar heat instead of reflecting it back into space, since ice reflects about 90 per cent of the indecent solar radiation compared to the absorption of 60 per cent of solar radiation by an open ocean surface devoid of ice.
In the subarctic region, dieback of the boreal forest and desiccation of peat deposits is leading to uncontrolled peat fires (such as those that plagued Russia in the summer of 2010) increases with warmer weather. This burning will further enhance greenhouse gas emissions.
We expect the Arctic will switch from being a carbon dioxide sink to become instead a source of greenhouse gases if seawater temperatures rise 4-5°C.
The rate of Arctic climate change is now faster than ecosystems and traditional Arctic societies can adapt to. Tipping points do not have to be points of no return. Several tipping points, such as the loss of summer sea ice and melting of permafrost, may be reversible in principle – although hard in practice.
However, should these changes involve the extinction of species – such as polar bears, walruses, ice-dependent seals and more than 1000 species of ice algae – the changes could represent a point of no return.
The Arctic crisis is a test of our capacity as scientists, and as societies, to respond to abrupt climate change. We need to stop debating the existence of tipping points in the Arctic and start managing their dangerous reality.
Carlos Duarte is Director, Oceans Institute at University of Western Australia. This article was originally published on The Conversation – theconversation.edu.au
Unless it appears in part II, to which I don't have access, there was no mention of climate change, yet it is fossil fuels, such as coal, natural gas etc. that are mostly responsible for it. Living outside of the U.S. I get the impression that as a nation, the U.S. doesn't give a damn about the topic. Perhaps it is too hot a political potato to mention, but until as a nation it does address the issue, it is goint to be too hot a climate instead. One that is going to result in a lot of deaths. I suppose that as most of those deaths will not be of U.S. citizens, it doesn't matter a lot, Oh, hum, 'Do unto others, etc' can go hang, eh? One is forced to wonder who is going to be willing to buy these exports from a nation that so obviously doesn't give a hoot about the well-being of those whom it sees as its customers.
It is also worth noting that recently the release of methane in the Arctic has increased significantly and is generally seen as being due to the melting of methane hydrates following the increase in temperatures that is being experienced there. According to Professor Chris Rhodes "It is believed by some that the Permian-Triassic (P-T or PT) extinction event, sometimes informally called the Great Dying, which was an extinction event that occurred approximately 252 million years ago, forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, which extinguished the life of up to 96% of all marine species and 70% of terrestrial vertebrae species" was caused by a sudden release of methane. Methane release is a positive feedback mechanism. If the current increase in methane release continues, we could see a catastrophic release, with a runaway increase in temperatures.
O.K. there are uncertainties, but with that level of uncertainty regarding the safety of a model of aircraft the whole fleet would have been grounded instantaneously. We can always catch another aircraft. We only have one earth and the U.S., especially those currently seeking to run for office, seems hell bent on trying to destroy it. Why? Because attempts to combat it might hurt the economy! One wonders what they will do with the 'mess of pottage' they get in return.
Quote from C Matrenson"
I don't normally wade into these waters mainly because the entire topic of global warming, for many, comes down to a matter of belief and is therefore subject to a rapid escalation of emotions.
I will say that as a former computer modeler I am quite leery of big models because I know the limitations. Among them are sensitive dependence on initial conditions (the so-called butterfly effect especially prominent in chaotic systems), the length of time being modeled (longer = less accurate), and getting your variables both completely defined and their feedback loops properly adjusted.
The more non-linear the system, and the less 'testable' it is, the trickier it is to model. For example, modeling the path of a drop of dye in a glass of water is still pretty much a parlor trick with models making beautiful approximations but not so much actually predicting an actual event (i.e. revealing all the actual swirls prior to a drop being placed in a glass of water). And here we are talking about a very limited system with a relatively few variables; temperature, density of both fluids, shape of the vessel, size of the drop, height of its drop, etc and one that is easily subject to repeated experimentation and repetition to the investigators' delight and refinement.
Now let's fast forward to a system (climate) with hundreds if not thousands of variables, some of which may not yet even be characterized (or discovered), many of them not directly testable, with unknown feedback parameters requiring vast ranges to be applied (think back to the butterfly effect here) all being cast forward many years, if not decades. Suffice it to say that some caution is warranted. "
from Post #248
You are right about the various weaknesses in the models but the analogy you give about trying to predict an event doesn't correspond to what climate models are trying to do. Predicting an event is a weather model which is all but impossible beyond a few days (perhaps 5) due to the "butterfly effect". So how the heck can you ever predict climate 50-100 years in the future? Predicting the climate is vastly simpler.
Let me explain. First, climate and weather are not the same thing. Climate is average weather. The general definition is the average weather over at least 30 years. The analogy I use in classes is as follows. If I had to predict the height of the next person to enter a building, I'd have a real tough time and probably have a substantial error rate because I might get a basketball player or a midget (this is trying to predict an event). However, if I had to predict the average height of all of the people who had entered the building during a given year I would likely be able to 'predict' it very closely (similar to predicting climate). In this analogy, predicting average height change over time (e.g. climate change) could be done if I had better information on the changing ratio of males/females attending the university or changing nutrition availability for populations that would affect the average height I see from year to year.
The oft used quote from George Box, "All models are wrong, some models are useful" applies. The biggest problem for the models that I see right now is that they don't account for feedbacks in the system well if at all. Global Climate Models (GCMs) have, for the most part been wrong, but they have been wrong in one direction. Real warming is happening much faster (decades) than the models indicate they should.
So yes, caution is warranted, but I think that where the caution should lie is being misplaced.
As an aside, in response to the podcast yesterday by Chris, I opened a "Definitive" thread in the dungeon because I didn't know about this rip roaring ongoing discussion. Based on the forum guidelines, I thought this subject was relegated to that location and couldn't find any materials on global climate change there so I decided to take the plunge. Any advice on how to proceed?
Do you have a good sense of how big a threat the thawing of the permafrost is with other releases of methane in northern climes? Is it a tipping point problem, or is it happening slowly enough that there won't be a self perpetuating cycle of heating before the methane is removed from the atmosphere? BTW, how is it removed from the atmosphere?
It probably is no worse threat than it was 900 years ago when Greenland was home to a thriving agricultural community and the arctic was a good deal warmer than today. Mark should comment on that as well.
I'm not familiar with the particulars of Greenland when the Norse settled there, but it strikes me there may be some significant differences. First is the speed with which the warming happened then and now. If warming is gradual, releases of methane would also be gradual and could be removed from the atmosphere without reaching critical levels since persistence of methane is quite a bit less than CO2. Warming is happening faster than most scientists predicted now, particularly in the Arctic, which might lead to greater concentrations of methane than during the Greenland warming. BTW, agriculture is returning to Greenland now:
This is all speculation, which is why I asked.
According to the temperature records that have been extracted from the Greenland ice cores, temperatures there appear to have risen about 0.8 C between 850 and 900 A.D. That is about the same 0.16 C per decade rise that has occurred globally three times within the last 150 years (1860-1880, 1910-1940 and 1975-2000). I have not seen anything that gives the corresponding rates of these relatively recent temperature increases just specifically for Greenland. It might be higher, but if so, it likely was much the same in each of the periods of rapid rise within the last 150 years.
Doug and Stan,
This is one of the less well defined feedbacks. There is obvious melting. We have so-called drunken forests in the arctic where trees are tipping every which way as the underlying permafrost melts.
Various melt lakes and ponds are steadily bubbling methane. I've seen videos of scientists lighting off the bubbles (link). I've also seen a somewhat alarming increase in the amount of melt ponds across siberia in recent years. (see image)
This is all concerning but we don't have a good handle on why methane levels rise in spurts. Here is the most recent atmospheric concentrations at Mauna Loa. Got this image from Wikipedia.
Putting things in a longer perspective though this is 800,000 years of atmospheric concentrations of methane (image from CSIRO). 800,000 years below 750ppb and the a sudden increase to 1800 ppb in the modern era.
Concentration increases in the last century are not subtle. Methane is a more powerful greenhouse gas than CO2, generally considered about 20 times on a molecule to molecule basis, luckily there is about a thousand fold less of it than CO2. The good news is that it oxidizes within a few decades. The bad news is that the byproducts are H2O and CO2, additional greenhouse gases.
If you want to see a worst case analysis, for a sudden 100-fold increase in arctic methane release, in case a tipping point is reached check out this link (link). The bottomline would be an increase to roughly an equivalent of 500-750ppm CO2. We are currently just north of 390ppm. This wouldn't be a runaway greenhouse but it would be at worst case IPCC scenarios.
Doug and Stan, (hmm, not sure why it wouldn't post the images, they show up on my screen but dissappear in the post - below I stick links to them instead.
Scroll down to the drunk forests inthis link (link)
Scroll down to siberian melt lakes (link)
Recent methane (bottom right is best image)
See image here (link)
My entire post was quoting from Dr Chris Martensons' only comment in this thread.
I had posted it here in response to recent queries here as to his position on AGW, and it appeared they had not seen this posting by him.
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