I listened with interest to Kevin Trenberth on the latest Climate Show describing how the increased water vapour in the atmosphere resulting from human-caused global warming is leading to greater extremes in weather events. It sent me back to take another look at the section in James Hansen’s book Storms of My Grandchildren where he explains the greatly increased strength of storms we can expect as the century unfolds, unless we leave most fossil carbon in the ground. I reviewed the book a while back on Hot Topic and thought it worth outlining more closely here, as an extension of my review, Hansen’s argument in the ten pages where he specifically addresses the storms of which the book’s title speaks.
As ice sheet disintegration begins in earnest he writes of a chaotic transition period in which our grandchildren will live the rest of their lives. Ice sheet disintegration in Earth’s past needed millennia, but human forcing is so much more powerful than natural forcings that ice sheets will respond much more rapidly.  Currently most of the recent energy imbalance due to increased greenhouse gases in the atmosphere is warming the ocean and only a small fraction is being used to melt ice. This division of excess energy will shift more to ice melt as the ice sheets are softened up and begin to discharge ice to the ocean more rapidly.
Increased ice discharge in both West Antarctica and Greenland will cool the neighbouring ocean. Although Greenland is not as vulnerable to rapid collapse as West Antarctica is it can lose mass fast enough to influence North Atlantic Ocean surface temperature. This freshwater melt will also decrease the salinity and hence the density of the water, making it less able to sink to the ocean bottom as it currently does, where it feeds the ocean “conveyor†circulation and allows warmer water to move north to replace it. If that deepwater formation slows down the regional North Atlantic cooling from ice melt will be enhanced.
Meanwhile in low latitudes the atmosphere and the ocean surface will be getting warmer and warmer as the century proceeds. This will exacerbate trends already apparent such as mountain glacier melting, expansion of dry sub-tropical regions, more intense forest fires and competition for diminishing freshwater supplies. There will be increased desiccation but in other times and places heavier rain and increased floods.
The greatest impact warming will have on storms is through the increase in water vapour it causes. Atmospheric water vapour increases rapidly with only a small temperature rise. Latent heat is the energy acquired by water vapour when it evaporates. When it condenses that latent energy is released as heat that is potentially available to fuel a storm. The storm types driven by latent heat include thunderstorms, tornadoes, and tropical storms such as hurricanes and typhoons. The greater availability of this heat will mean that the strength of the strongest storms will increase as global warming increases. There will also be an expansion of the regions liable to severe storms.
This is just the beginning. There are three ratcheting effects in waiting. One is the development of more powerful and destructive mid-latitude or frontal cyclones. They depend on the temperature difference between the cold and warm air masses as well as on the amount of moisture in the atmosphere behind the warm front. The melting ice sheets will exacerbate this once they begin to disintegrate rapidly enough to keep regional ocean surface temperature from rising as fast as continental temperatures and temperatures at lower latitudes. Increased moisture content in lower- and mid-latitude warm air co-existing with ice-cooled polar air masses will increase the intensity of frontal cyclones.
The consequences of even a metre of sea level rise combined with increased storm strength are horrendous to contemplate.
The second ratcheting is far greater. It occurs when the ice sheets’ rapid disintegration causes a sea level rise measured in metres. Eventually ice sheets begin to disintegrate at rates of several metres of sea level rise per century. We could soon create conditions that guarantee this happening, but it is likely to be several decades before a rapid sea level rise begins. Hansen notes that we have been surprised by how fast some other climate changes have occurred, but for the moment offers his best estimate of when large sea level change will begin as during the lifetime of his grandchildren. The consequences of even a metre of sea level rise combined with increased storm strength are horrendous to contemplate. He offers a few examples of what it will mean for vulnerable places in various parts of the world.
The third ratcheting effect would be the melting of methane hydrates. Of greatest concern are those in sediments on the ocean floor, because of their great volume. Hansen relates the chance of their melting to possible ocean circulation changes because of the freshwater additions to both the North Atlantic and Antarctic Oceans through ice sheet disintegration. Global ocean circulation reorganised during the Paleocene-Eocene thermal maximum about 54 million years ago when a sudden large global warming occurred and deep water formation took place in the Pacific rather than the North Atlantic, flooding the ocean floor with warmer Pacific Ocean water. If that happens again, melting methane hydrates, there will be no plausible way for humans to reverse the change of ocean circulation. The released methane added to the high levels of carbon dioxide will result in a huge planetary energy imbalance and the remaining ice on the planet will disappear. That means a sea level rise of 75 metres.
Hansen, as usual, communicates the science to his readership with clarity and fully appropriate urgency. Â These are not remote consequences he is exploring, but at least strong possibilities and in some cases inescapable certainties. No lay reader prepared to take a little time to come to terms with the concepts can fail to understand the serious risks we run if we carry on exploiting fossil fuels. No policy maker can claim not to have been made aware of the danger of continuing on our present course.
Hansen is not off on some flight of fancy of his own. He is interpreting solid mainstream science. It’s from that base that he says towards the end of the book that our planet is in imminent danger of crashing and that the fight for effective policies to prevent that is the most urgent fight of our lives.
Nice summary Bryan.
I couldn’t agree more with your conclusion. This is no flight of fancy – it is solid science. The danger signals are there for every one to see.
Those who do not wish to see, will never understand.
In his latest paper, Hansen points out that the response of the ice sheets so far is consistent with an ice loss doubling time of as little as ten years. Things may be better than that, but we won’t know for a while.
Should make this one required reading in high schools. Better yet, let the children keep the books when they’re done, maybe some parents will read it if it’s laying around the house. (Hell, maybe give copies out through plunket and neonatal classes as well.)
I can assure you that if you try to distribute climate change propaganda within schools anywhere near me, I will be making a lot of noise about it.
You might want to read the book, John, before you dismiss it as propaganda.
If you look for the word “will” in the above article, you will find that it occurs maybe 18 times.
How many times does the word “may” appear? (Zero)
I don’t think many scientists, climate or otherwise, talk in such certainties about the climate system.
We simply don’t understand it enough.
I don’t believe that statements of such certainty are honest reflections of science.
Please address the arguments Hansen makes, rather than sling accusations of dishonesty around.
It’s quite certain that large, dangerous changes are in order, which you would know if you paid attention to the scientific literature. It being the future, there will always be uncertainty as to exact timing,
Example: The measured poleward movement of the descending branches of the Hadley cells (~140 miles so far), i.e. the expansion of the subtropical climate zone, which will result in overall drying of the affected land areas, and in fact already is, although these are early days. Please do try to explain what is incorrect about this statement.
There are lots of other examples.
It’s quite certain that large, dangerous changes are in order
So what do you mean by “quite certain”?
100%?
99.9%
95% ?
And please define “large” and “dangerous”
If you cannot define these terms in scientific words, then you are engaging in activist politics, not science.
Precise knowledge of the future is impossible, and not necessary. In this case, we know enough about the bad things that might happen to know that we need to do something. Uncertainty is not an excuse for inaction – quite the reverse. Uncertainty increases risk, and we need to take the dangers into account when deciding how to act.
You’re the one who doesn’t/won’t understand. Care to comment on the poleward march Steve refers to (and which has been mentioned previously on this site?) The effects in the SW and SE of Australia are already evident.
The “we don’t understand” mantra used by obstructionist deniers exactly parallels the “no proof” and “controversial” mantras emanating from tobacco companies ad nauseum.
I havent read Hansens book, but I note the IPCC states the weaknesses and uncertainties in its case. In fact its lead statement admits uncertainty. In contrast Books like Air Con and commentators like Leighton Smith are completely dogmatic.
And lowering the overall signal to noise ratio.
What schools need these days is more signal and less noise.
And you can help out by keeping your noise to yourself.
John D’s reply moved to open thread. Please discuss there, not here.
John,you’re clutching at straws. Hansen is a scientist. His work is always hedged with appropriate caveats. Some of the instances of “will” in the post may be down to me and I’m not going to go through it to determine that. But you don’t seem to understand that what Hansen is saying is that certain consequences will follow if, for example, the ice sheets begin to disintegrate. There can’t be much “may” about some of those. You haven’t looked at the writing of many climate scientists if you think Hansen is out on his own. He’s admittedly often in front of the field at times in the past, and he’s not one for reticence, but he’s part of the main body of a now well-established science.
He himself has considered the matter of scientific reticence in this paper.
Here’s an extract:
“Caveats are essential to science, being born in skepticism, which is essential to the process of investigation and verification. But there is a question of degree. A tendency for `gradualism’ as new evidence comes to light may be ill-suited for communication, when an issue with a short time fuse is concerned.”
In terms of what proof might be required, here is the standard which our expert Environment Court uses. They are talking about radiation from cellphone towers, which it found had little risk of ill effects:
“As we have observed, almost all evidence in the Environment Court relates to the future and thus has an hypothetical element. Before an hypothesis can be considered by any Court, there must be a basic minimum of evidence to support it. But in the case of any hypothesis about a high impact risk a scintilla of evidence may be all that needs to be established in the Court’s mind to justify the need for rebuttal evidence. In other words that evidence, slight as it may be, is enough to raise a reasonable doubt in the mind.
….
To fall within s 3(f) of the Act as a potential effect of low probability and high potential impact an effect must not be simply an hypothesis: there must be some evidence supporting the hypothesis. This evidence may consist of at least one of:
(1) consistent sound statistical … studies of a human population; or
(2) general expert acceptance of the hypothesis; or
(3) persuasive animal studies or other bio-mechanistic evidence accompanied by an explanation as to why there is no epidemiological evidence of actual effects in the real world; or
(4) (possibly) a very persuasive expert opinion.
It is important that the evidence need only fall into one of the categories before the Court will take it into account — if there was evidence falling in all four then the hypothesis would be established ‘hard’ science.”
Shirley Primary School v Christchurch City Council
[1999] NZRMA 66
On this basis, climate change passed from hypothesis to hard science some years back. And the Hansen/Makiko paper on SLR falls into the category of “a very persuasive expert opinion”, which we should be very, very concerned about.
Sorry Tom, I don’t buy your argument at all.
Comparing cell towers with climate policy and rapid decarbonisation of major economies is like comparing gardening with the EU Agricultural Policy.
Rapid decarbonisation? The most optimistic plans I have seen for achieving zero-carbon economies is on the order of 30 or 40 years. You think that is rapid?
Or are you just being alarmist and trying to make people scared of decarbonisation in order to promote your agenda?
CTG,
30-40 years to achieve zero emissions is extremely rapid and virtually impossible by many accounts.
I could provide figures to back up my statement but from the trite nature of your comment I assume that I am wasting my time.
“30-40 years to achieve zero emissions is extremely rapid and virtually impossible by many accounts.”
Humm…. now it seems to be you who is talking in terms of definitive predictions here.
Would you at least agree that under the weight of the accumulated evidence for AGW and the role of CO2 a reduction as much as feasible should be called for?
If scientists had discovered that a 10Km diameter asteroid would hit Earth with a very high probability in 50 years time wiping out large parts of our civilization, would you still want to wait and see for more “evidence” or would you undertake what can be done to deflect it as soon as practical?
While the asteroid and the presumed damage is easy to understand, the gradual nature of climate change is much harder to comprehend in its gravity, even though the end result of the two events may ultimately not differ by that much.
Please stop patronising me with these stupid analogies.
The number of nuclear power stations/windfarms/solar stations that need to be deployed on a daily basis in order to achieve zero emissions in 30-40 years is simply not possible. It defies economic and physical laws.
Please do provide numbers. Otherwise people might think that you are just hand-waving.
I don’t think 40 years is particularly rapid.
Take cars, for example. How long does the average car last? How many times would the average household change cars over a 40 year period? Is it really impossible to imagine that over 40 years the majority of people would be able to switch to electric vehicles? I’m sure there will still be some people, like you, who refuse to accept any amount of evidence, and will cling to petrol-powered cars no matter how high the cost of petrol goes, but most people will start to think that EVs make a lot of sense once petrol goes above $2.50/litre. Which will be in a couple of months, apparently, never mind 40 years.
You seem to think like a politician. 40 years is an inconceivable time period for a politician, who generally regard anything beyond an election cycle as “long-term”. Is your real name Rodney, by any chance?
CTG,
I can provide some numbers from Roger Pielke Jr’s book “The Climate Fix”. Chapter 4 – “Decarbonization Policies around the World”
There are a lot of graphs and figures in this book, and if you are interested in climate policy it might be worth your reading it.
Take, for example, Australia. In order to replace its coal stations with nuclear, it would have to build 57 nuclear power stations (taking into account future growth of the economy)
Similarly, replacing the current capacity with solar would require 3,333 Clonclurry equivalents, or 24 coming online every week between 2010 and 2020.
These “edge-case” scenarios are useful in discussing energy policy, because it gives some insight into the feasibility of the options.
Mere arm-waving is not enough. The UK has effectively consigned itself to the economic dustbin. Recently, the head of the National Grid announced that always-on power is likely to be a thing of the past.
And why should we need to continue supplying the same amount of power for activities that could quite easily continue, unaffected, using half or less of the current wasteful approach.
Why build a power station when changing building regulations would obviate the need for heating & cooling better designed factories, offices and homes? A better designed structure could quite easily be heated/ cooled/ managed with a few PV panels rather than a massive take from a centralised power distribution network. Merely getting rid of the 10-15% losses in transmission would avoid the need for yet another several power stations.
There are many and better solutions to power supply than thinking we just go on doing as we’ve done for a handful of generations. The next handful of generations could be a lot better off if we just stop thinking that what we’re used to is so obviously the best. It isn’t.
Sorry I can’t respond to adelady’s comment inline. However, your comment again is pure arm-waving.
You need to come up with numbers.
Of course, we all strive for energy-efficiency. It makes sense on every level (Note to Steve Bloom, sorry if this bores you)
However, if you are going to plan an energy infrastructure based away from FF, then you actually have to come up with some numbers.
This is how it works in the real world. Unfortunately, it doesn’t seem to be the same world inhabited by our politicians.
John you – and the rest of the “business as usual” crowd will have to eventually get your heads around the fact that this Planet is INCAPABLE of sustaining western life as we know it today – whether or not – we continue (at our peril) to burn fossil fuels. The consumption by the Western World is such that we are already far outstripping the Planet’s resources. We – that’s you and I and everyone here and our parents and possibly grandparents have all lived as if there was no tomorrow as far as sustainable living is concerned. Today each person on the Earth has about 2 hectares of land to support themselves. However we in NZ require on average around 10 hectares. People in Afganistan survive on about half a hectare. Earth overshoot day – the day on which the Earth goes into overdraft and consumes the resources of future generations occurs earlier and earlier every year.
http://postgrowth.org/natures-overdraft-notice-earth-overshoot-day/
It simply has to stop. We cannot continue to live in this wasteful and opulent way.
Your whole argument is based on the premise that we must continue to live in the lifestyle to which we have become accustomed. But that is an unsustainable position. It has been calculated that to support the whole population of the Earth in the manner of the Western World would require 3 Planets.The Planet will simply not support it.
Sooner or later if we continue to try to live with “business as usual” we are going to run up against diminishing resources – not just fossil fuels – but land, water, materials, but perhaps the first will be water. The consequences of which will be that we will simply HAVE to change our lifestyles to more sustainable ways.
Transitionin to a low carbon economy by 2040 would be very challenging, but I suspect if we tried other better energy sources would be rapidly found, a lot of its about urgency. Look at the technology that came out of WW2, just 5 years. Nuclear power just for starters.
You might recall how serious air pollution was in the 1950s, those kiler smogs. Nixon I think was presedent in America. He mandated a 90% reduction in particulate emissions within one year, a staggering requirement.
The auto industry testified under oath before congress it was impossible and would bankrupt them. Nixon held his ground, and one year latter the reductions were fully implimented and profits were hardly affected.
John D, you have successfully derailed this comment thread. The post is on the warnings of a notable and serious climate scientist whom you in your ignorant arrogance have characterised as a dishonest propagandist. Somehow you have manoeuvred away from the topic and are now treating us to your views on the impossibility of a transition away from fossil fuels in time to avert the worst of the dangers scientists like Hansen see looming ahead. Nowhere along the line have you addressed any of the specific points Hansen makes, (nor, incidentally have you paid any attention to the numerous posts in Hot Topic which address the feasibility of the transition to decarbonised economies) and by now the thread has probably run its course. Depressing, but one suspects exhilarating from your perspective.
Perhaps, Ã la Tim Curtin and Girma at Deltoid, John could be given his own thread to confine his activities to? Having the same tired old muck tossed indiscriminately and ad nauseam at everything really does become rather tedious… and to quote Morrissey – ‘that joke isn’t funny anymore‘!
Worth considering, at least. I did it for Roger Dewhurst, and he’s not seen around here much these days… 😉
Bryan
I am sorry if I derailed this comment thread. It wasn’t my intention.
I’ll keep my posts in the open thread (or Twilight Zone for those of that disposition) in future.
Bear in mind that all my posts are moderated anyway.
For goodness sake Hot topic show some courage. You are worse than scepticalscience endless warnings and a do nothing attitude. You need to listen to “The Super Nannny” warnings must be followed by action!Presumeably this is a science site not a free for all for the lunatics.
Throw people that derail things and their posts onto some open thread or general comments thread, then we can all have a bun fight together there if we wish, and they cant complain about being shut out. And in no way should sceptics be shut out. I cant now even remember the title topic of this thread.