Climate Change, July, 2023: Not the Mild Good News I Had Hoped For

Disclaimer:  I am now retired, and am therefore no longer an expert on anything.  This blog post presents only my opinions, and anything in it should not be relied on.

This April (after a long hiatus from blog posting) I hoped to be able to post a climate change piece with a few bits of good news among the bad.  CO2 as measured at Mauna Loa, it appeared, had cut its year-to-year growth rate nearly in half.  The use of solar power rather than coal or oil for energy in homes and cars was slowly growing as price drops for solar continued and the US passed the Inflation Reduction Act with incentives for solar and electric-vehicle use, as well as embedding climate change efforts more deeply in the US government bureaucracy.  Arctic sea ice appeared for the last six years to have reached a new equilibrium level, never breaching the 2016 lows.

And then, from April to July, several things happened almost simultaneously:

1.       James Hansen et al published a paper arguing that (a) global warming for a doubling of CO2 was most likely to be not 4 degrees C as he had previously estimated, but 4.5 degrees C, (b) this would be increased by an inevitable decrease in human-caused aerosols starting a few years ago, and (c) it was now possible to project to some extent the degree to which this warming would happen over the next century.

2.       “Hothouse Earth”, by Bill McGuire, talks specifically about what we may expect in the next 30-50 years in particular, including a halving of global food production.

3.       Monthly CO2 (Mauna Loa) saw a very large rise in April, to a rate 3 ppm above April 2022, and May and June show similar jumps, while our best measure of yearly CO2 jumped to 421 ppm in June, more than 50% above its 1850 280-ppm baseline – implying, together with Hansen et al’s work, that 3 degrees C of global warming above that time period is now “baked in” and unavoidable.

4.       Global sea surface temperatures are now well into record territory, and sea temperatures around Florida are now around 95 degrees, hot enough to kill coral and some fish.

5.       Antarctic sea ice has diverged dramatically from recorded extents – since it is winter in the Antarctic, this means that warm winds from an incipient equatorial El Nino have prevented as much as 1/3 of historical sea ice refreezing.  It would seem inevitable that new record lows will continue to be set all the way to Antarctic sea ice minimum in late January, with follow-on effects on Antarctic land ice melting and hence ocean level rise.

6.       Dangerous air quality from Canadian wildfires has affected the northern US, while record heat, often around 110 F, is affecting the southern US.

7.       From July 3^rd to the 5^th, global record land temperatures for apparently the last 125,000 years occurred, reaching above 17 degrees C.

Looking Forward with Great Wariness

All of this is worrying enough.  But it is also the case that by all accounts, a new El Nino is starting, and may well last for a year or more.  The past few times an El Nino has occurred, if I remember correctly, CO2 has spiked upwards at a record pace and global land temperatures have also risen significantly.  The prospect of grueling heat waves not just this summer but next is certainly a cause for major concern.

I should also, I suppose, mention articles suggesting that the melting of permafrost with attendant methane release is continuing to ramp up.  It is not clear how much this increases global warming independent of CO2 increases:  methane (CO4) is more powerful in the atmosphere as a greenhouse gas, but much less prevalent than CO2.  At the same time, a certain amount of methane breaks down in the atmosphere to CO2, thus increasing carbon dioxide concentration.

Overall

My conclusion from all of the above is that most if not all of our decrease in CO2 emissions is being “drowned out” by the shift to El Nino, economic rebound from COVID, decreases in aerosols, and increased permafrost melting. 

One good thing is that popular news outlets aside from The Guardian – including CNN, AP, and the New York Times – are willing to report that today’s weather extremes are indeed caused by climate change.  On the other hand, I see not only that 150-odd Republican Representatives (a majority of Republicans in the US House of Representatives) are still classed as “climate deniers”, but also that an increasing number of people at the other extreme have given up hope of doing anything about climate change – often because they sense correctly that the 1.5 degree C target for “avoiding disaster”, and also the 2 degree target for “avoiding catastrophe” are certain to be overrun.

However, this, I must emphasize, is not, in my view, the proper way to view the future.  What lies beyond these targets – the next doubling of CO2, and the next – increases the scale of the disaster almost tenfold.  It is true, I think, that once one target is breached, the next is harder to stop short of, because both of feedbacks from initial warming and increasing sunk costs of fossil-fuel infrastructure that makes its replacement harder.  However, those feedbacks decrease over time to nothing if we succeed in slowing CO2 emissions dramatically, and the success of solar power shows that green energy can succeed even if it means uprooting what’s there for a whole new system.

And so, our initial successes count far more towards preventing disasters numbers 2 and 3 than they do towards avoiding today’s disaster; and the consequences of success or failure in our quest are far greater.  Think 2 billion lives lost or 8 billion rather than 500 million and that may give you an idea of what is at stake.   Thus, what is happening is a matter for heartbreak and anger at those responsible, but not for despair.  On the contrary, it is a matter for steadfast effort. 

As was once said, it’s the only game in town, and you lose no matter what you do.  But if you do it right, you won’t go broke before the game ends.  Or, to put it another way, humanity and nature will not by and large die if we try well enough, although we cannot prevent mass murder, both before and after we die.  And that’s the best obituary we can hope for.

CO2 Update: Slightly Less Bad News

 Disclaimer:  I am now retired, and am therefore no longer an expert on anything.  This blog post presents only my opinions, and anything in it should not be relied on.

I continue to monitor the CO2 results measured at Mauna Loa, as pretty much the best indicator out there as to whether our recent efforts at mitigating climate change are having any effect at all, or whether the rate of growth of atmospheric CO2 continues to increase as it has for the last atmospheric growth. 

I have been doing this since around 2010, and have only seen two months’ data over that time that suggested there might be some leveling of the CO2 growth rate.  Of course, that is only the first step in saving the planet – the second is to start decreasing the growth rate, the third is to drive the growth rate to zero, and the final step (which is the point at which we will actually be doing something positive about climate change) is to pursue decreases in CO2 until it reaches about 280 ppm (a far harder task than boosting its level). 

The first of the two data points was last May.  For no obvious reason (and therefore the likeliest reason was actual effectiveness in cutting CO2 emissions) May was almost flat compared to April, although April was a normal-growth month and in all previous years since 2010 May has been significantly above April.  Oh well, maybe it was a one-time event.

But then came March of this year.  As I have never seen before, March has been significantly below February.  It still appears likely that May will end up above 420 ppm – an important milestone, since average yearly atmospheric CO2 was around 280 ppm in the early 1800s before human-caused global warming began.  Each doubling of CO2 is projected to be associated with 3-4 degrees Celsius of global warming (perhaps two-thirds of that being directly caused by CO2 itself), so reaching 420 ppm should in the long run be associated with 2-2.67 degrees of warming.  In any event, reaching 420 ppm is clearly unadulterated Bad News.

However, the second downturn from trend in the last year suggests that maybe, just maybe, we are reaching the point of a level growth rate in atmospheric CO2.  This is slightly supported by the fact that the last four years of CO2 growth rates have been in the 2.3-2.5 range – a period which seems to have mixed mild La Nina (inhibiting CO2 growth rates) and neutral (no effect on CO2 growth rates) weather.  Since this is not too far from the typical case across history (El Nino being more of an exception than La Nina), I conclude that there are therefore three possible signs that a leveling of CO2 growth rates may have been reached.

Thoughts on Implications

I admit that I base my thinking loosely on a draft paper by James Hansen et al in which he argued that the maximum number of doublings of CO2 would be three or four (somewhere above 2240 ppm).  This would be achieved, iirc, if approximately 60-70% of the fossil-fuel reserves identified at the time of writing (2013 or so) were burned.  At the pace at which use was increasing at the time, the appropriate amount of fossil fuels would have been burned and its CO2 moved into the atmosphere in 50-60 years time.  Thus, a continued rise in the growth rate of CO2 represents this worst-case scenario:  if the last nine years continued the growth-rate rise trend, then we would have narrowed the time for avoiding the worst-case scenario to 40-50 years in the future – not to mention drastically decreasing the chances of avoiding the first and second doublings. 

Therefore, I argue, what we would have achieved by leveling the growth rate of atmospheric CO2 is at least more time to avoid the worst-case scenario, and at best a major decrease in the probability of reaching the worst-case scenario.  That is the sense in which I say, this is slightly less bad news.  Considering that the worst-case scenario as described by Hansen involves the death of most of the human race, not to mention much of the rest of the environment – in this nightmare scenario, if you go outside in most places to work during the day during most of the year and stay out more than an hour, you will die of heat stroke – anything that reduces that likelihood is to be celebrated.  But the first two doublings involve the deaths perhaps of hundreds of millions to a billion, so we should be clear-eyed about increasing toughness of the job ahead, even with this news, and recognize that those who seek to prevent us from decreasing that growth rate for their own selfish purposes may well be murderers beyond the scale of the Holocaust, or the Holodomor, or WW II. 

But enough of gloom.  Go enjoy the slightly less bad news, he said on his birthday.

The Climate Science Global Warming Model, Part I: Today's Human-Caused Global Warming

To repeat:  In this series of blog posts, I attempt to give an overall view of the physics/chemistry-based climate science dealing with climate change and today’s global warming.  I do so because I can’t find an overall summary such as the one I’m about to try to create.  My hope is that readers will understand why this science makes me so alarmed and seemingly so pessimistic.  As always, misunderstandings and misstatements are my fault and do not reflect on the science itself.

In this post, we take a look at what climate science has to say about today’s human-caused global warming.  This episode of global warming beyond what would be expected from the Milankovitch cycle and underwater volcanism (that is, from a “Goldilocks” steady state that would soon begin to slowly decrease towards an Ice Age) has already taken us to global temperatures not seen for the last 1-5 million years. An additional 1.5 degrees C is already “baked in” – that is, the temperatures have not yet caught up to the atmospheric carbon level, but even with zero carbon emissions from now on, and without some technology that we do not presently have, we will still see this additional increase to a new “semi-steady state”.

The key difference between all previous episodes of global warming and this human-caused one is that for the first time ever, carbon stored in animal and vegetative matter beneath the Earth (including the shallow parts of the oceans) is being brought above ground and burned, injecting into the atmosphere much of the carbon so stored over the last 100 million to billion years of life on Earth.  Specifically, this means oil, natural gas, and coal, as well as the tar sands and oil shale that also contain “fossils”.  If all of the rest of this “energy reserve” were to be used in the same way over the next 100 years, then atmospheric carbon would probably reach more than 2000 ppm, and possibly as high as 4000 ppm.

As should be clear from my last blog post, the main difference in climate behavior from previous episodes of global warming is that atmospheric carbon injection is happening far faster:  about 100 times faster.  Thus, parts of the climate process that operate to slow global warming or return to a previous “steady state”, which operate much more slowly, have very little impact on this global warming.  More specifically, “weathering” has very little impact, and oceanic ice-creation mechanisms that operate to keep the Arctic filled with sea ice also cannot operate very well.

Let’s be a little more specific about the last point.  The Oceans in today’s Earth operate in a great surface/underwater loop or “conveyor belt”.  The Gulf Stream’s warm water moves up to a point near Greenland, cooling as it goes.  When it reaches that point, it dives down below the surface and begins a journey south to the Antarctic Ocean, and from thence up the Pacific to a point near Alaska and Siberia, where it resurfaces and completes the loop back to the Gulf Stream.  This is called a “conveyor belt” because it transmits surface ocean temperature changes to the deep Ocean over a period of about 100 years. 

When global warming causes sea ice to melt more at the “dive-down” point, that sea ice is fresher water, and therefore warmer (salt prevents water from freezing until it reaches about 29 degrees F, at which point the salt is expelled from the sea ice).  That warmer, fresher water slows or even stops the Gulf Stream from diving down at the dive-down point.  That, in turn, slows down or stops the rest of the Gulf Stream if it goes on too long.  If it doesn’t, the fresher water, being more easy to freeze, reforms near the dive point, and the “diving down” resumes.  In effect, up to a point, this circulation cycle acts to retard or reverse the loss-of-sea-ice albedo effects of global warming.  However, the faster the global warming, the less effect this mechanism has.

Climate Effects of Today’s Global Warming

Today’s global warming has and will have (remember, further temperature increases are “baked in”) effects on global climate especially in four ways:

1.       Temperatures in the Arctic and Antarctic warm perhaps 5-10 times as much as those nearer the Equator.  Also, winter temperatures warm more than summer ones, and night temperatures warm more than day ones.  The key effect from this on the Northern Hemisphere is that the temperature differential between Northern Eurasia and Northern America and the Arctic decreases, while weather patterns on both sides of that divide have more energy to stay on the “wrong side”.  The initial result is that weather systems on both sides linger longer, and are more extreme.  Boston saw almost-record cold last January for long periods of time, as Arctic weather came down and lingered; the Arctic saw several unprecedented warm spells from the south over this New Year, including a 22-hour period where the temperature was above freezing.  In the long run, however, the warmth from global warming will dominate the cold from the Arctic: a few million years ago, 360 ppm atmospheric carbon saw a subtropical Arctic.

2.       The atmosphere has more energy (heat) and more rain, making for stronger and windier extreme-weather events.  It appears that increased incidence of tornadoes and increased top winds in hurricanes are to some extent caused by these temperature increases.  Likewise, heavier rain/snow when it occurs and greater wind-driven oceanic “storm surges” onto land are definitely occurring and are effectively caused by global warming.

3.       Climate “zones” move poleward, i.e., northward/southward.  In particular, subtropical zones with high heat and massive droughts extend northward/southward.  In 2050-2070, America/southern Canada (except New England/NY), pretty much all of Europe, the Middle East, India, and 2/3 of China, as well as Australia and Tasmania, are projected to be suffering Dust-Bowl-like droughts, if things go on as they have.  This may or may not be true if very strong action is taken that reduces drastically human contributions to atmospheric carbon.  Because of the unusual speed of global warming, the majority of ecosystems in these area cannot move northward effectively and are faced with extinction in the next 100 years.  Also, a decreased availability of water for farming due to loss of snowpacks and overuse of aquifers combined with the drought conditions places perhaps ½ of all of today’s arable land under threat.

4.       Land ice and snow melts exceptionally rapidly.  Melting of sea ice only causes slight ocean rise, as ice displaces as much area as cold water; oceanic heat increases (slow to happen, as noted) expand and therefore raise the oceans less than 10%.  Land ice and snow melting, however, translates directly into sea-level rise.  The key areas here are Greenland, West Antarctica, and East Antarctica.  A domino effect in the Arctic, which has already started, removes the sea-ice barriers to increased flow of Greenland glaciers into the oceans surrounding it, leading to a doubling of net land-ice loss there every 10 years.  West Antarctica has already begun the same process, especially in the Antarctic Peninsula, and it appears that East Antarctica is doing so as well.  Greenland may contribute as much as 10 feet of sea-level rise this century, while West Antarctica may well also contribute that amount.  In the longer term (again, this may be “baked in” by a 360-ppm atmospheric carbon level), sea level rise may reach a maximum of 220-240 feet.  This would submerge 1/3 of the world’s present arable land in salt water.  If we add 30-foot-higher storm surges that “salt” water supplies inland, most of today’s coasts to 50-100 miles inland will be uninhabitable.  Thus, for example, in the US, Florida, Louisiana, Alabama, and Mississippi will effectively cease to exist.

There are also indirect “feedback loops” related to climate change that make temperature increases per atmospheric-carbon doubling 4 degrees C rather than 2.5 degrees C.  The three key effects there are increased albedo due to ice/snow replacement by water/rock/earth, melting of permafrost (which has already begun to occur) that leads to release of permafrost carbon into the air, which in turn increases temperature, and emergence of “black carbon” from the layers of melted ice, which “dirties” and thereby increases the albedo of remaining snow/ice as well as adding carbon to the atmosphere.

Finally, we should note some of the things that do not affect today’s climate change in the medium to long term:

1.       Above-water volcanism and “nuclear winter”.  These create winter-like conditions in which the temperature drops drastically.  In both cases, the particles that create these conditions linger for 1-7 years, but the net effect on underlying climate change is exactly zero:  if you double atmospheric carbon during the 1-7-year period after an eruption or nuclear-winter episode, at the end of 7 years a temperature increase of 4 degrees C will be “baked in.”

2.       Changes in the amount of cloud cover caused by climate change.  Studies have shown that, if anything, these increase temperatures slightly. 

3.       Aerosol pollution.  This is most frequently a side-effect of coal burning, and results in increased “smog”-related airborn particles that decrease temperatures significantly.  However, as China is now finding out, aerosol pollution can only counteract increased atmospheric carbon up to a point, after which people suffering aerosol pollution will die.  Thus, it now appears extremely likely that overall aerosol pollution will decrease over the next century, “uncovering” the temperature increases that were masked by the pollution increases.

4.       Methane emissions will increase sharply, but it now appears that their overall effect will be relatively small.

Summary

What worries climate scientists the most about today’s global warming is its unprecedented speed and extent, both of these being the result of humans rapidly and massively extracting and injecting into the atmosphere hundreds of millions of years of sequestered carbon primarily from dead animals and plants. The resulting feedback loops and processes, less checked than ever before by stabilization processes, enhance the immediate temperature effects of the new atmospheric carbon and have reached the point of oceanic saturation where much of the carbon now in the atmosphere will not be “cycled out” for thousands of years.

But there is another key implication of today’s process of global warming.  At every stage, the climate effects of doubling atmospheric carbon are 2-10 times greater – including the negative ones.  Thus, while storm surges once we enter the 500-1000 ppm atmospheric carbon stage, the frequency of 100-mph storms now equals that of 80- or 90-mph storms in the previous stage; and the damages from 100-mph winds is 10 times that of 80-90-mph winds. To fail to prevent 500 ppm atmospheric carbon is an argument for redoubling our efforts to prevent 1000 ppm atmospheric carbon, not for giving up, because the consequences of failure to prevent each stage get progressively worse.

What is the worst that can happen, and what does it require?  According to a recent study by Hansen et al, the “can’t get any worse” scenario happens when we burn a certain amount of today’s fossil fuel reserves within the next 100-200 years:

If we burn all the coal plus a very minor amount of everything else, we reach “worst consequences.”

If we burn all of the oil, 33% of the coal, and none of the gas/tar sands/oil shale we reach “worst consequences”.

If we burn 17% of the coal, 50% of the natural gas, and all the tar sands/oil shale/oil, we reach “worst consequences”.

What are the worst consequences?  Here’s a brief summary of those:

In Hansen’s worst-consequence world, humans could survive below the mountains during the day outside only for short periods of time during the summer, and there would be few if any places to grow grains. 

In my version of Hansen's worst-consequence world, we would try to survive on less than 10 % of today's farmland, less than 10 % of the animal and vegetable species (with disrupted ecosystems), and practically zero edible ocean species, in methane-heavy mosquito-infested peat swamps that must be developed before they can be farmed, in dangerous weather, for thousands of years.

My final blog post on this subject will examine certain implications of climate science on effective ways to combat today’s global warming.

Climate Change Update: The Fundamental Things Still Apply, and Honest Cost-Benefit Analyses Are Dangerously Flawed

It has been hard to find a good reason to post an update on climate change, although superficially there is a lot of relatively good news.  Climate change is now an acceptable part of TV “nature” documentaries, to which so many are addicted; for the first time, China has committed to less coal use and has delivered in a measurable fashion; there is the outline of a global plan for carbon-emission reduction as we head into the latest climate-change summit; and even the rhetoric of the Republican party has allowed for a candidate (Kasich) who admits that serious climate change is happening and something needs to be done about it.  And then there is Pres. Obama, who is the first major political figure afaik who has admitted that we not only need to cut back on carbon emissions but also keep a large chunk of our remaining fossil fuels in the ground indefinitely.

The Fundamental Bad News Still Applies

So why do I feel that these are not significant enough to discuss in detail?  For this simple reason:  as far as we can tell, the rise in atmospheric carbon continues not just in a straight (rising) line, but in a slow acceleration.  To put it another way, if atmospheric carbon simply kept increasing at its present rate of about 2.5 ppm per year, by 2100 it would reach about 625 ppm, corresponding to (as per Hansen) to a 4.4 degrees C or 7.6 degrees F global temperature rise.  If, however, it continues to accelerate at its present rate, according to one estimate it will reach 920 ppm by 2100, baking in a whopping 7.5 degrees C or almost 14 degrees F increase.  When I say “baked in”, I mean that we may not see that amount of temperature increase in 2100, but in the 30-50 years after 2100, much of that temperature increase will show up.

Meanwhile, the climate change this year is unfortunately proceeding as seemed likely 5 years ago.  The El Nino that causes temperature spikes was delayed, but as a result is now almost certain to be the strongest on record, causing an inevitable huge new high in global land temperatures (last year was the previous record) of about 2/3 of a degree F above the old record.  Moreover, it now seems that the El Nino will continue for quite a few months next year, almost guaranteeing a 2016 global land temperature significantly above 2015. It would not be surprising if 2015 plus 2016 totaled a full 1 degree F jump. 

And finally, the “strange” rebound in Arctic sea ice volume after 2012 is clearly over, and our best prognostication suggests that 2016 volume at minimum will be in second place after 2012 – suggesting that at least a linear reduction in volume over the last 40 years continues.  As a result, Greenland’s glaciers continue collapsing and should contribute several feet to sea level rise this century.  Some forecasts even contemplate a 26-foot rise from all sources (Greenland and Antarctica, primarily) by 2100, although more sober analyses still suggest somewhere between 6 and 16 feet.

In other words, the fundamentals of human-caused climate change continue to apply, however we may delude ourselves that our measures up to now have had a significant impact.  Like Alice in The Looking Glass, we will probably have to run twice as fast to get anywhere, and then four times, and then ...

Honest Cost-Benefit Analysis Continues to be Flawed

To my mind, the only really good news, if good news there be, is that I am beginning to see honest cost-benefit analyses – the analyses that potentially really try to face the costs and benefits of the mitigation required to do something significant about climate change.  For example, one blog post noted that most analyses failed to reflect people’s difficulties in moving when climate change or climate change mitigation requires it (meaning that a few do).  It has been absurd, watching commentators assuming that loss of 50-90% of present arable land and the necessary water translate easily into new but temporary growing spots, with the costs of moving to those locations vanishing by the magic of the so-called free market.

However, an analysis published in MIT’s Technology Review identified one barrier that, in the author’s mind, doomed any near-term conversion to solar energy:  Faced with utilities’ resistance to meshing the existing electrical grid with individual solar installations, homeowners are faced with a large installation cost that make solar uncompetitive in the home in the near to medium term.

I don’t think the author’s cost-benefit analysis – for that is what it boiled down to – is obviously flawed.  But I do believe that it suffers from several key flaws specific to climate change:

1.       It assumes a certain infrastructure (the existing grid) without considering the ways in which that grid will become comparatively more and more costly, despite temporary fixes, as changes in climate make some locations so hot that air conditioning costs shoot through the roof, some locations underwater or damaged by storms, and some locations with a different mix of heat and cooling that the grid was designed for.  A solar arrangement is not affected as much by this, because it is necessarily more distributed, can de-novo provide better architecture-based earth-derived heating and cooling, and involves less sunk-cost coal/oil/gas storage for heating.

2.       It fails to handle the “disaster scenario” in which the benefits of present cheaper energy fail to outweigh the future costs of disaster caused by everyone coming to the same don’t-change conclusion.  In other words, each decision analyzed is not a one-off nor is it isolated – most if not all people will come to the same conclusion and act the same way, and that is the situation that must be modeled.  If we all conclude that sea-level property will be fine for 40 years and can be sold thereafter to a greater fool, in a global context we quickly run out of fools, and then we can sell to nobody.

3.       It assumes governments will be able to act as the backstop/insurer of last resort.  To put it another way, in the typical situation, if businesses fail, governments are expected to handle a portion of the costs of bankruptcies (or to backstop those who do, as in the case of AIG), to provide unemployment benefits so that a pool of labor remains, and to support repair of “common” infrastructure such as roads and heating/cooling when businesses can’t.  However, when the effects are close to simultaneous and truly global, most governments are hard put to come up with the necessary support.  This, in turn, creates chaos that makes the next (and greater) crisis harder to handle.  Effectively, there is a point beyond which all countries are under such stress that despite reallocation of business investment, economies start shrinking and the ability to handle the next stress becomes less and less.  Some estimates put that point as early as the 2060s, if we continue as we are going.  So the cost of each individual decision that affects carbon pollution mitigation should be factored into a cost-benefit analysis, as well.

Recommendation:  Face The Facts

In this situation, I am reminded by an episode in fantasy author Stephen Donaldson’s first series.  He posited a leper placed into a world in which an evil, powerful character seeks to turn a wonderfully healthy world into a reflection of the leper’s symptoms:  rotting, smelling, causing numbness – and a prophecy says that only the leper can save this world.  The leper befriends a “High Lord” dedicated to fighting the evil character, and says, essentially, “Look, you’re trying you’re best but you’re failing.  Face facts!”  The High Lord, hearing this from the one person who can save his world, says, very carefully, “You have a great respect for facts.”  “I hate facts,” was the passionate response, “They’re all I’ve got.”
The point, as I see it, is not to look a grim outlook in the face and give up.  It is, rather, in everything done about climate change to understand how a particular effort falls short and how even grimmer forecasts should be factored into the next effort.  It is understanding that even as we fail to avoid the consequences of the first 4 degrees C of global warming, we redouble our efforts to avoid the next 4 degrees.  It is cutting away the non-essentials of curbing population growth and of dealing with immediate crises such as the Paris bombings, and seeing that in part these are manifestations of stresses in society that global warming is exacerbating, and therefore the primary focus should be solar now now now, or a reasonable equivalent.  And it is performing, individually and collectively, the kinds of honest cost-benefit analyses that will confront us with facts that we might not want to face, but which will lead us as quickly as possible in the right direction.

I hate climate change facts.  They’re the closest thing to hope I have.  Season’s greetings.

James Hansen’s Climate Change Magnum Opus: Unsurpassed Horror and Sad Beauty

I warn you that this description of the latest draft paper by James Hansen and others should horrify you, if you are sane.  After Joe Romm first published its sound bite (30 degrees Fahrenheit increase if most fossil fuels are burned, 50 degrees at higher latitudes), I delayed reading it in detail. Now that I have, I find it builds on his (and others’) 40 years of work in the area and the latest research to provide an up-to-date climate change model whose implications are mostly more alarming than any I have seen elsewhere. 

What follows is my layperson’s attempt to summarize and draw further conclusions. I scant the discussion of new analyses of previous episodes of global warming (and cooling) that allow the development of the new model, focusing instead on the mechanisms and implications of the model.  Please note that, afaik, this is the first model that attempts to fully include the effects of methane and permafrost melting.

It’s About CO2

The first insight in the new model I summarize as follows:

As atmospheric CO2 increases or decreases, global average temperature increases or decreases proportionally, with a lag either way typically of a few decades.

This increase or decrease can be broken down into three parts:

1.       The immediate effect of the CO2 itself -- perhaps 60% of the total effect.

2.       The immediate and “over a few decades” effect of other “greenhouse gases” , or GHGs (here we are talking particularly about the methane in permafrost and methane hydrates on the continental shelves, released by warming, as well as GHGs such as nitrous oxide) – perhaps 20% of the total effect.

3.       The so-called “fast feedback” effects, in which the released CO2 and other factors (e.g., increased albedo) lead to additional warming “over a few decades”.

Two quick notes:  First, Hansen does not do my split; instead, he distinguishes between the effects of CO2 and the effects of other GHGs over the medium term (about 75-25) and then separately distinguishes between the immediate overall “climate sensitivity” and the medium-term or total “climate sensitivity” (again, about 75 % immediately and 100 % in the long term).  Second, the “over a few decades” is my interpretation of how quickly “X times CO2” seems to match global temperature data over more recent sets of data.  Hansen might very well say that this may or may not occur quite this rapidly, but it doesn’t matter to him because even with a thousand-year time frame for the full effect, CO2 will not be recycled out of the atmosphere for “few thousand years”, so we still reach the full “climate sensitivity”.

Just to get the usual objections out of the way, Hansen is not saying that CO2 always leads the way – on the contrary, in Ice Age scenarios in which a certain point in a Milankovitch cycle causes extreme winters in our northern hemisphere, leading to increased glaciation and therefore decreased albedo and CO2 release to the atmosphere, CO2 follows other factors.  Today, however, primarily because of fossil-fuel emissions, CO2 is leading the way.

A sub-finding, still important, is that there is a linear relationship (again, sometimes with a lag of decades) between deep-ocean temperature change and atmospheric temperature change (expressed as “the change in temp at the surface is somewhere between 1.5 and 2.5 times the change in temp of the deep ocean” – or, about 67% of the global temperature increase goes into surface temps, 33% into deep ocean temps).  I include this because it seems that the recent “slowdown” in global surface temperature ascent is primarily caused by increased accumulation in the deep ocean.  However, again in a relatively short time frame, we should go back to more rapid average global surface temperature increases, because we’re still increasing atmospheric CO2 rapidly and 2/3 of that will start again going back into surface temps.

The Effect of “CO2 Plus” Is Bigger Than We Thought

In the past, Hansen among others has seen the effect of doubled CO2 as somewhere in the 2-3 degrees Celsius range.  Now, he sees a range of 3-4 degrees C – apparently, primarily because he now takes into account “other GHGs”.  To put it more pointedly, in my own interpretation:

Each doubling of CO2 leads to a global temperature change of 2.25-3 degrees Celsius (4-5.4 degrees F) “over a few decades”, and to a change of 3-4 degrees C (5.4-7.2 degrees F) “over 1 or 2 centuries.”

I mention this not only because the consequences of today’s global warming are more dire than we thought (i.e., the effects of that warming, immediately and over the next century or two), but also because many of us are still hung up over that “stop emissions and hold the increase to 2 degrees C” target that was the main topic at recent global governmental summits.  The atmospheric CO2 level at the beginning of the Industrial Revolution was about 250 parts per million (ppm), and is now at about 400 ppm.  If you do the math, that means we have baked in at least 2.2-3 degrees C of global temperature increase already. After 15 years of inaction, that target now has zero chance of success.

At this point, I want to do a shout-out to those wonderful folks at the Arctic Sea Ice blog and forum.  Hansen specifically notes the data supporting melting of Arctic sea ice, plus collapse of the Greenland and West Antarctic ice sheets, at levels slightly below today’s CO2.  He also notes data supporting the idea that Greenland and West Antarctica can go pretty rapidly, “in a few centuries”, iirc – I interpret “in a few centuries” as within 250-450 years from now.

The Percent of Fossil Fuels We Need To Leave In The Ground Forever Is Greater Than We Thought

Before I get to the consequences if we don’t leave a percentage of fossil fuels in the ground, let’s see how the minimum amount of fossil fuels burned before we reach “worst consequences” has changed. Today’s estimate of total recoverable fossil-fuel reserves (coal, oil [primarily tar sands and oil shale], and natural gas) is about the equivalent of 15,000 Gt C (billions of tons of carbon emitted).  Of this, coal is about 7.3-11 Gt C, and the rest is split approximately equivalently between natural gas and tar sands/oil shale. Originally, we thought that burning 10,000 Gt C in the next century would get us to “worst consequences”.  Now, Hansen places the correct amount as somewhere between 5,000 Gt C and 10,000 Gt C.  Reading between the lines, I am placing the range as 6,000-7,000 Gt C, with 5,000 Gt C if we want to be ultra-safe, and I’m estimating coal as 60% of the emittable total, 20% tar sands/oil shale/oil, 20% natural gas.  Note, btw, that according to Hansen fossil-fuel emissions have increased consistently by about 3 % per year since 1950, including last year. At that rate, we’d reach 6,000-7,000 Gt C in about 65-70 years.

Again, note that Hansen breaks the fossil fuels down as coal, traditional oil/gas, and oil shale/tar sands/fracked gas, so I’m guesstimating the equivalents.

So here’s the way it works out:

If we burn all the coal plus a very minor amount of everything else, we reach “worst consequences.”

If we burn all of everything but coal and 33% of the coal, we reach “worst consequences”.

If we burn 17% of the coal, 50% of the natural gas, and all the tar sands/oil shale/oil, we reach “worst consequences”.

So this, imho, is why I agree with Hansen that allowing the Keystone XL pipeline is “game over” for the climate, as in “worst consequences almost inevitable”.  The Keystone XL pipeline is a “gateway drug” for tar sands and oil shale.  The source (Alberta, Canada) has a large part of the known tar sands oil, and presents similar difficulties in abstracting and processing to oil shale.  It’s the furthest along in terms of entering the world market.  If that source succeeds, as the saying goes, once the nose of the camel is in the tent, you may expect the rest of the camel to enter.  In this case, if Alberta succeeds in getting the Keystone XL pipeline, it is probably the case that most of the tar sands and oil shale will be used; if not, probably not.

Right now, Alberta has no real buyers except the US, and the US is not set up to accept the oil, nor Canada to ship it to them in bulk.  The pipeline would effectively create an infrastructure to ship it, primarily to the rest of the world, which presumably would accept it – especially China – creating a market that allows Alberta profitability.  Alternatives are much more costly, are susceptible to pressure from the US, and would probably not be undertaken at all.  Note that increased shipment via truck is more costly, and would probably require major investments in truck structure, to handle the more toxic tar-sands crude, so that it is probably not a large-scale alternative that would make the project a success.  Likewise, trains and tracks to the Canadian ports to ship directly to world markets would probably prove too costly.

Now go back to the model.  It’s pretty darn likely we’ll burn 17% of the coal no matter what, and the majority of the natural gas.  Now add the tar sands and oil shale.  Worst consequences, here we come.

The Worst Is Likelier Than We Thought, Arrives Sooner, Is Almost As Bad As Our Worst Nightmare, And Is More Inescapable Once We Get There Than We Hoped

We’ve already dealt with “likelier than we thought”, and we can guess from the rapidity of response to atmospheric CO2 rise and the increase in the estimated climate sensitivity to atmospheric CO2 that it arrives sooner than we had projected. But what is this “worst consequences almost as bad as our worst nightmare”, and “worst consequences, once arrived, more inescapable that we hoped”?

For us, the worst consequences are not “snowball Earth”, locked in eternal ice, but “runaway GHG Earth” a la Venus, with the surface and air too hot and too acid to support water or any life at all (water vapor in the atmosphere vaporizes from the heat long before it reaches the surface).  It’s an inescapable condition, since once the atmosphere locks in the heat, the Sun’s heat from outside trapped by the CO2 and other gases in the atmosphere balances escaping heat from the troposphere (top of the atmosphere).  Hansen’s model shows that we are still 100 million to 1 billion years from being able to reach that state, even by burning all fossil fuels in a gigantic funeral pyre. 

The worst consequence, as cited before, is therefore as cited at the very beginning, Joe Romm’s sound bite:  30 degrees F increase globally, 50 degrees in the high latitudes.  Here’s Hansen’s take on what that means:  it will take all areas of the Earth except the mountains above 35 degrees C “wet bulb temperature” during their summers.  That in turn, according to Hansen, would mean the following: 

In the worst-consequence world, humans could survive below the mountains during the day outside only for short periods of time during the summer, and there would be few if any places to grow grains. 

Effectively, most areas of the globe would be Death Valley-like or worse, at least during the summer.

Here I think Hansen, because he properly doesn’t diverge into movement polewards of weather patterns and the effects of high water and possible toxic blooms, underestimates the threat to humanity’s survival.  Recent research suggests that with global warming, tropic climates stretch northwards.  Thus, projections for the US (not to mention Europe below Scandinavia, Australia, southern Africa, and southern Russia) is for extreme drought.  How can this be, when there will be lots of increased water vapor in the air?  Answer: it will be rare in falling, and far more massive and violent when it does.  The heat will bake the ground hard, so that when it does rain, the rain will merely bounce off the ground and run off (with possible erosion), rather than irrigating anything.  Add depletion of aquifers and of ice-pack runoff, and it will be very hard to grow anything (I suppose, mountains partially excepted) below Siberia, northern Canada/Alaska, and Scandinavia. 

However, these have their own problems:  rains too massive (and violent) to support large-scale agriculture – which is why you don’t see farming on Seattle’s Olympic Peninsula.  The only “moderate-rainfall” areas projected as of now, away from the sea and the equator, are a strip in northern Canada, one in northern Argentina, one in Siberia, and possibly one in Manchuria. Most of this land is permafrost right now.  To even start farming there would require waiting until the permafrost melts, and moving in the meantime to “intermediate” farming areas.  Two moves, minimal farmland, and greater challenges from violent weather.  Oh, and if you want to turn to hunting you’ll be lucky if you have an ecosystem that supports top-level meat animals, not to mention the 90% of plant and animal species that will likely be extinct by then. As for the ocean, forget about it as a food source, unless you like jellyfish (according to research done for the UN recently).

In my version of Hansen's worst-consequence world, we would try to survive on less than 10 % of today's farmland, less than 10% of the animal and vegetable species with disrupted ecosystems, and practically zero edible ocean species, in territory that must be developed before it is usable, in dangerous weather, for thousands of years.

Hansen notes that one effective animal evolutionary response to past heat episodes has been hereditary dwarfism.  Or, as I like to think about it, we could all become hobbits.  However, because we are heading towards this excessive heat much faster than in those times, we can’t evolve fast enough; so that’s out.

What about inescapable?  Well, according to Hansen, CO2 levels would not get out of what he calls the “moderately moist greenhouse” area for thousands of years, and would not reach close to where we are now until 10,000-100,000 years hence.  By which time, not only will we be dead, but most of humanity, if not all.

Now, I had feared the Venus scenario, so the worst consequences are not as bad as I thought.  However, the increased estimate for temperatures in the moderately moist greenhouse and the wet bulb temperature consideration makes the next-worst scenario more likely than before to end humanity altogether. 

Snowball Earth:  Sad Beauty of a Sidelight

Having said all this, Hansen at least gives a beautiful analysis of why we don’t wind up a “snowball Earth” (the opposite scenario from a “runaway greenhouse”).  He notes that once the Earth is covered with ice, carbon can’t be recycled to the Earth via “weathering” (absorption from the atmosphere by rocks whose surfaces are abraded by wind and water).  So volcanic emissions and the like put more and more carbon dioxide in the atmosphere, until the temperature warms up enough and melting of the ice begins.  Apparently, evidence suggests that this may have happened once or twice in the past, when the Sun was delivering less light and hence heat.

Envoi

The usual caveats apply.  Primarily, they fall in the category of “I was reading Hansen out of fear, and so I may be stretching the outer limits of what may happen, just as Hansen may be understating out of scientific conservatism.”  Make up your own mind.

I am reminded of a British Beyond the Fringe comedy skit about WW II, suitably amended:

“Go up in the air, carbon. Don’t come back.”

“Goodbye, sir.  Or perhaps it’s ‘au revoir’?”

“No, carbon.”

And what will it take for humanity to really start listening to Hansen, and to the science?