Malthus and Global Warming

[starcanuck64]

It will be interesting to see the next IPCC report, the 2007 report placed the effect of aerosols at a -1.6 w/m^2 forcing I think, with a lot of uncertainty.

[profloater]

Malthus argument was flawless in its simplicity. Darwin also noted in his first chapter that any species produces enough offspring to populate the whole world quickly (and therefore must run into limits) but it was Lovelock who tied the two together in his Gaia hypothesis.

Mankind has the innovative advantage but sadly no useful foresight overall so surely we will hit limits. Populations have risen and fallen before, famine and disease go hand in hand. In the 13th C two years of rain in Europe, probably due to a volcano, led to more than halving of the population through famine and the black death.

But timing is everything, so maybe we can get through this year!!! (Corn prices hit new record)

[Ara Pacis]

Malthus argument was flawless in its simplicity. Darwin also noted in his first chapter that any species produces enough offspring to populate the whole world quickly (and therefore must run into limits) but it was Lovelock who tied the two together in his Gaia hypothesis.

Mankind has the innovative advantage but sadly no useful foresight overall so surely we will hit limits. Populations have risen and fallen before, famine and disease go hand in hand. In the 13th C two years of rain in Europe, probably due to a volcano, led to more than halving of the population through famine and the black death.

But timing is everything, so maybe we can get through this year!!! (Corn prices hit new record)

But mankind isn't a single entity, as I pointed out earlier. We like to think it is, but we're fractured into factions by race and ideology, among other things. Birthrate has historically been a method of intentionally asserting political dominance. When roman birthrate was down, into the roman cities migrated the outlanders from various parts of the periphery, such as from the Middle East and then the Germanic migrations. Without getting into religion or politics or race, even some modern groups (especially those of low social status) encourage a high birthrate while (or because) other groups who currently have power have low birthrates and will eventually lose their dominance. the problem with taking the "long view" of humanity is that different assumptions drive different perceptions of reality and different concepts of the future reality.

[Maur]

There are a lot of unknowns when it comes to methane clathrates, first of all how much there is of them, estimates range from 2,000 to 24,000 Gts.

Climate and tectonics has favoured the buildup of large amounts of methane clathrates near the poles in recent epochs, isostatic rebound from ice loss and melting permafrost could help release large amounts of CH4.

Upper estimate of 24 teratons of methane? Heh. How much would temperature rise if that was released?

[starcanuck64]

Upper estimate of 24 teratons of methane? Heh. How much would temperature rise if that was released?

Only a fraction of the overall clathrate deposits are predited to become unstable, but if you look at the Paleocene-Eocene Thermal Maximum there was about a 6C degree rise over a period of about 20,000 years, we've already experienced about a 0.8C rise as of the middle of the last decade. Based on carbon isotope ratios in sediments from that time it's estimated that about 3,000 Gts of methane clathrates were released in several pulses in the PETM.

So we're experiences much quicker warming due to the rapid increase in atmospheric GHGs and land surface changes in conjunction with unusually large deposits of one of the most powerful GHGs in potentially unstable deposits. If we do start seeing large releases of methane then I'd think that a 6C rise in average global temperature is more than possible.

[Maur]

Only a fraction of the overall clathrate deposits are predited to become unstable, but if you look at the Paleocene-Eocene Thermal Maximum there was about a 6C degree rise over a period of about 20,000 years, we've already experienced about a 0.8C rise as of the middle of the last decade. Based on carbon isotope ratios in sediments from that time it's estimated that about 3,000 Gts of methane clathrates were released in several pulses in the PETM.

So we're experiences much quicker warming due to the rapid increase in atmospheric GHGs and land surface changes in conjunction with unusually large deposits of one of the most powerful GHGs in potentially unstable deposits. If we do start seeing large releases of methane then I'd think that a 6C rise in average global temperature is more than possible.

I was suprised, because Copenhagen agreed to limit CO2 emmissions to 500 or so gigatons in order to stay under 2 degrees increase. So, 48 times more, and methane not CO2 to boot sounded like a runaway greenhouse effect.

[starcanuck64]

I was suprised, because Copenhagen agreed to limit CO2 emmissions to 500 or so gigatons in order to stay under 2 degrees increase. So, 48 times more, and methane not CO2 to boot sounded like a runaway greenhouse effect.

There's a thread here on that somewhere.

Reading James Hansen's book Storms of My Granchildren, he puts a Venus Syndrome at somewhere between +10-20 w/m^2 forcing, we're at about +4 w/m^2 now with some offset from aerosols. That seems a little small to me, there have been periods where the CO2 concentration has spiked dramatically but there hasn't been a runaway greenhouse effect. The K-T impact at 65 Mya and the freeze-fry cycles between about 700-600 Mya saw CO2 levels much greater than we have now or probably will have.

What a large pulse of methane into the atmosphere may do is create such rapid change that many species may not make it through the bottleneck.

Keep in mind only a fraction of the methane clathrates will possibly be released, and that could be a thousand years from now.

[starcanuck64]

They're now looking at Antarctica as an important reservoir of methane, which could be released as the ice sheet thins.

http://www.huffingtonpost.com/2012/0...n_1840996.html

“You have perfect conditions, and the ice has been there for 30 million years,” Wadham said, “so there’s been plenty of time for methane to build up.”

It takes a combination of cold and pressure to turn methane into methane hydrates, and if either one of these conditions is relaxed, the methane can escape. In the Arctic, it’s the loss of cold scientists worry about as the seawater overlying methane-rich sediments continues to warm.

In the Antarctic, Wadham said, “it’s the drop in pressure that would come if the ice sheets get thinner.” It’s not happening yet, but that could change if the temperature of waters surrounding the Antarctic continent continues to rise.

[Maur]

There's a thread here on that somewhere.

Reading James Hansen's book Storms of My Granchildren, he puts a Venus Syndrome at somewhere between +10-20 w/m^2 forcing, we're at about +4 w/m^2 now with some offset from aerosols. That seems a little small to me, there have been periods where the CO2 concentration has spiked dramatically but there hasn't been a runaway greenhouse effect. The K-T impact at 65 Mya and the freeze-fry cycles between about 700-600 Mya saw CO2 levels much greater than we have now or probably will have.

What a large pulse of methane into the atmosphere may do is create such rapid change that many species may not make it through the bottleneck.

Keep in mind only a fraction of the methane clathrates will possibly be released, and that could be a thousand years from now.

Thread on what exactly? Copenhagen, runaway GH or methane?

Haven't read Hansen. That said, 650mya had lower solar insulation, but indeed that leaves out the PETM.

[starcanuck64]

Thread on what exactly? Copenhagen, runaway GH or methane?

Haven't read Hansen. That said, 650mya had lower solar insulation, but indeed that leaves out the PETM.

Thread on the Venus Syndrome and whether or not it becomes inevitable at a certain point we're already close to I think.

There was less insolation, but there was also a massive build-up of atmospheric CO2 and other greenhouse gases as the planet went through the alternating freeze-fry cycles. The almost complete ice cover on the Earth prevented the uptake of CO2 from tectonic activity from the ocean and weathering of rocks. From what I recall the possible swings in average global temperature went from about -60C to +50C, we're not going to experience anything close(hopefully).

http://en.wikipedia.org/wiki/Snowball_Earth

That doesn't mean that a whole host of activities in conjunction with climate change don't pose a serious challenge to our eventual survival in the next several centuries if we continue a business as usual model of energy production.

[publiusr]

-- but it was Lovelock who tied the two together in his Gaia hypothesis.

Also with Lynn Margulis--who sadly died late last year http://en.wikipedia.org/wiki/Lynn_Margulis

remember that much of our CO2 is locked into chalk and other carbonate rock--limestone. No water meant that Venus couldn't trap its atmosphere to ground.

[profloater]

So, looking again at the OP whether Malthus is relevant to GW, current comments suggest it is GW which threatens to limit our population rather than no food, but of course there is a strong link there. Malthus did not foresee that we would actually change the planet but his reasoning was basically sound wasn't it? The trouble with prediction is that any fool can get the themes right, it is the timing that is so hard.

[starcanuck64]

Timing is pretty difficult to predict with the huge number of variables involved, all we can say with any real certainty is that the global environment is in a state of flux and it will continue to be as long as it's being forced further.

If you look at the conditions present in the US this summer it gives some indication of what's to come, almost 2/3s of the nation was in drought conditions at the height of the heat wave.

Also a large percentage of people depend on protein from the ocean in their diet, what happens as the result of ocean acidification and the loss of important species and ecosystems like coral reefs as climate change progresses.

Even in the best of times, survival is a marginal experience for a huge numbers of people, how many more are going to be forced into this position and what will that mean to overall stability globally.

[Joe Durnavich]

Aren't droughts in the midwest U.S. due to the Atlantic being in its warm phase?

For what it is worth, from the Wikipedia page

"Recent research suggests that the AMO is related to the past occurrence of major droughts in the US Midwest and the Southwest. When the AMO is in its warm phase, these droughts tend to be more frequent or prolonged. Two of the most severe droughts of the 20th century occurred during the positive AMO between 1925 and 1965: The Dust Bowl of the 1930s and the 1950s drought. Florida and the Pacific Northwest tend to be the opposite—warm AMO, more rainfall.[6]"

[starcanuck64]

Aren't droughts in the midwest U.S. due to the Atlantic being in its warm phase?

For what it is worth, from the Wikipedia page

"Recent research suggests that the AMO is related to the past occurrence of major droughts in the US Midwest and the Southwest. When the AMO is in its warm phase, these droughts tend to be more frequent or prolonged. Two of the most severe droughts of the 20th century occurred during the positive AMO between 1925 and 1965: The Dust Bowl of the 1930s and the 1950s drought. Florida and the Pacific Northwest tend to be the opposite—warm AMO, more rainfall.[6]"

This article shows how the kind of extreme hot weather events often associated with drought conditions are becoming much more frequent in the Northern Hemisphere.

http://www.giss.nasa.gov/research/news/20120806/

The statistics show that the recent bouts of extremely warm summers, including the intense heat wave afflicting the U.S. Midwest this year, very likely are the consequence of global warming, according to lead author James Hansen of NASA's Goddard Institute for Space Studies (GISS) in New York

[Jens]

but his reasoning was basically sound wasn't it?

I don't think it really was. His argument was that population growth is exponential, whereas food product only increases linearly, so you will eventually run out of food and people will have to starve. What he basically misunderstood is that humans plan. For example, a lot of people in developed countries today only have one or two children not because of ecological awareness, but because they look ahead and realize that college costs xxx dollars, and understand that it is unrealistic to have more. Other animals don't do that as far as I know. We may end up harming the environment beyond repair, but that's not exactly what Malthus was saying. He was saying it was inevitable that life would always be short and brutish.

[Joe Durnavich]

This article shows how the kind of extreme hot weather events often associated with drought conditions are becoming much more frequent in the Northern Hemisphere.

http://www.giss.nasa.gov/research/news/20120806/

There's that, but I was wondering more about the mechanism that caused the midwest drought in the sense that there has to be some regional pressure system, the oceans, or something that leaves the midwest dry. Or am I wrong about that and can global warming also directly create weather events?

The paper, Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States published in 2004, predicted a midwest drought

"Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought."

But maybe that is like predicting that Tom and Katie would break up. You kinda sorta expect that stuff after a while.

[Robert Tulip]

His argument was that population growth is exponential, whereas food product only increases linearly, so you will eventually run out of food and people will have to starve. What he basically misunderstood is that humans plan.

The globe is in fact in a Malthusian situation because agricultural productivity is growing slower than population. There is a significant food security gap between projected production and need. Climate change only makes bridging the food production gap much more difficult.

[HenrikOlsen]

I don't think it really was. His argument was that population growth is exponential, whereas food product only increases linearly, so you will eventually run out of food and people will have to starve. What he basically misunderstood is that humans plan. For example, a lot of people in developed countries today only have one or two children not because of ecological awareness, but because they look ahead and realize that college costs xxx dollars, and understand that it is unrealistic to have more. Other animals don't do that as far as I know. We may end up harming the environment beyond repair, but that's not exactly what Malthus was saying. He was saying it was inevitable that life would always be short and brutish.

Remember that he was living in a time where such planning wasn't possible, it was a time where about half the fertile women could be expected to be pregnant at any given time.

[Antice]

There's that, but I was wondering more about the mechanism that caused the midwest drought in the sense that there has to be some regional pressure system, the oceans, or something that leaves the midwest dry. Or am I wrong about that and can global warming also directly create weather events?

The paper, Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States published in 2004, predicted a midwest drought

"Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought."

But maybe that is like predicting that Tom and Katie would break up. You kinda sorta expect that stuff after a while.

Global warming is not triggering neither drought nor floods. The real effect of AGW is to alter the weather patterns subtly in a manner that both can and will amplify the weather patterns we already have. this round of drought was triggered by the same ocean currents that triggered the last big drought in the US. What AGW does add to this tho is a deepening of the drought pattern, by adding days to the length of it and a couple of degrees or so to the max temperature during the heat wave.

Ironically. whenever one part of this planet is in drought we get floods in another part of it. This is so because all that evaporation going on has to come down as rain somewhere. the weather system is a closed system after all. if the drought severity is increased, then so is the flooding severity in that other location.

you can liken the weather to a sort of engine, and the climate as being a measure of how much fuel (energy really) is given to the weather engine. When the temperatures rise (energy in the system increases) the engine speeds up. everything goes faster so to say. this means that we get bigger storms, dryer droughts, and more precipitation where that happens. those snow records you heard about last year, those were fueled by AGW too, and you can expect those records to be broken again and again as the climate heats up. the temperature rise is not large, so in general. cold places will still get cold in the winter, and hot places will still be hot. that won't change much. it's the edge zones where we will notice the bigger difference as deserts will tend to grow, and thundra regions and ice sheets are slowly going to shrink.

[starcanuck64]

There's that, but I was wondering more about the mechanism that caused the midwest drought in the sense that there has to be some regional pressure system, the oceans, or something that leaves the midwest dry. Or am I wrong about that and can global warming also directly create weather events?


The paper, Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States published in 2004, predicted a midwest drought

"Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought."

But maybe that is like predicting that Tom and Katie would break up. You kinda sorta expect that stuff after a while.

From what I understand the timing and strength of some if not all of the basin wide ocean-atmospheric oscillations like ENSO and PDO have been changed by global warming.

Climate and weather are the result of complex systems constantly trying to balance out the differences in pressure and temperature on the Earth, if you start adding more energy into the system then those interactions are quite likely going to change. This can result in more of the extreme weather we've been seeing in the last few decades.

[kzb]

One thing people tend to forget is that, if I fit low-energy light bulbs and save money on my energy bills, that means I have more money to spend on other things.

Those other things are likely to require energy and may even have a carbon footprint exceeding the electricity that I have not used. Even if I don't spend it, my bank will lend out ten times what I have saved, probably to energy-requiring businesses.

[starcanuck64]

One thing people tend to forget is that, if I fit low-energy light bulbs and save money on my energy bills, that means I have more money to spend on other things.

Those other things are likely to require energy and may even have a carbon footprint exceeding the electricity that I have not used. Even if I don't spend it, my bank will lend out ten times what I have saved, probably to energy-requiring businesses.

It needs to be a system wide approach to dealing with greenhouse gas emissions and consumption in general. As the Internet expands it also uses huge amounts of energy, it's going to take some very creative solutions to bring things back into some sort of balance.

[Joe Durnavich]

About the mechanism behind the Midwest drought, then: Can we look at the drought, that one specific drought, and see global warming in it? That is, does global warming have any visibility here?

Thinking I might see a smoking gun in the statistics, I did look at the historical PMDI for a few of the Midwestern states and for the contiguous U.S. (here), but no increase in drought frequency or intensity really stands out to me.

[Jens]

The globe is in fact in a Malthusian situation because agricultural productivity is growing slower than population.

Though he specifically stated that the difference was that the growth of population is naturally geometric whereas that of agricultural production is linear. In the absence of planning, population growth surely is geometric, but Malthus was ignoring planning I believe. In Malthus's mind the problem was fundamentally unsolvable except through starvation, whereas I think most today believe that the situation is not really Malthusian.

[Jens]

Remember that he was living in a time where such planning wasn't possible, it was a time where about half the fertile women could be expected to be pregnant at any given time.

I don't know if impossible is really true, merely that it wasn't practiced. For one thing, I think that children were more economically advantageous to a family, relatively speaking. You didn't need to educate them much, and they could start working at the age of seven or eight I suppose. Now in some advanced countries you're lucky if they are working by the time they're 30!

[Antice]

One thing people tend to forget is that, if I fit low-energy light bulbs and save money on my energy bills, that means I have more money to spend on other things.

Those other things are likely to require energy and may even have a carbon footprint exceeding the electricity that I have not used. Even if I don't spend it, my bank will lend out ten times what I have saved, probably to energy-requiring businesses.

This is the core mechanic behind jevons paradox. increased efficiency does not reduce total consumption. that is why we need to focus on changing the way we produce energy, and not be distracted by those who claim that energy efficiency is going to save the day, because it simply can't because of this one simple consumption dynamic.

There are only one way to decrease consumption, and that is by decreasing the economy as a whole. (recession with all the joy's that bring with it)
Clearly this is not something people want?

[Noclevername]

There are only one way to decrease consumption, and that is by decreasing the economy as a whole.

Only one? That sounds a little extreme.

Per Wikipedia:

As the Jevons paradox applies only to technological improvements that increase fuel efficiency, policies that impose conservation standards and increase costs do not display the paradox.

In other words J's P is not a law of physics. It fails to take into account governmental, social and personal decision-making.

[Antice]

Only one? That sounds a little extreme.

Per Wikipedia:

In other words J's P is not a law of physics. It fails to take into account governmental, social and personal decision-making.

Jevons paradox has never been about physics. it's all about economics. the cases where it does not apply is in cases where costs are increased. the reason for that is because when a goods becomes more expensive it is used less. that is the market for this resource is diminished. (that is the definition of a recession)

Energy is something of a special case for jevons paradox. since this particular resource is needed in absolutely all aspects of life. when energy becomes more expensive the entire economy has to contract,(system wide recession) and not just a subset of it, like when iron becomes more expensive other materials can step in and replace it, thus only the iron portion of the market contracts, and is countered by a growth in economic activity elsewhere. When energy costs go up all prices has to go up as well after all. you can call this energy cost driven inflation if you want, but it's still a recession.

[Ari Jokimaki]

Thinking I might see a smoking gun in the statistics, I did look at the historical PMDI for a few of the Midwestern states and for the contiguous U.S. (here), but no increase in drought frequency or intensity really stands out to me.

There is a clear increase. From 1900 to 1970 running 10-year mean of this index varied roughly around -5. After 1970 it has varied roughly around +5 to +10. This change can quite easily be seen also in annual mean graph shown in the page you linked to.