Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity

Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity   by James Hansen (Kindle Ed. Dec. 2010)

Hansen is a brilliant scientist. His conviction in the dire power of climate change is very strong and he has been called an alarmist, as the title of the book suggests. Nevertheless, he presents a very good case with great detail and scientific rigor. This is definitely the most detailed book on climate change that I have found, by a scientist who has devoted his work to the study of climate. I do not agree with everything he suggests, particularly some of his policy recommendations, but his ideas are sound and should be considered.

I have recently read that he retired from his long career at NASA and is planning the life of an activist-of-sorts, providing scientific testimony for litigation, and opposing the dirtiest and most disruptive of fossil fuel extraction techniques, such as mountaintop removal for coal and tar sands oil extraction.

Hansen gives rather detailed accounts of his meetings with government officials at very high levels, mainly the White House and Congressional Climate policy groups – from the 2nd Bush administration on. He also talks about meetings with scientific groups and his foray into giving public talks focusing on the immediate dangers of climate change.

He notes throughout the book the influence of “special interests” – mainly fossil fuel lobbies, and government “greenwashing” – ie. making “business-as-usual sound as green as can be. These, he says, lead to a public that is not well informed. In my opinion, the two most important qualities a citizen should develop in regard to these issues are to be well informed and not overly biased in view. To become well-informed means to look at the issues from multiple perspectives. To be generally unbiased is to seriously consider the benefits of each perspective. Hansen has a lot of supporting data for his view. He does admit that there are still some uncertainties. His view, along with that of his friend Bill McKibben (author and 350.org founder), could be considered the most alarmist of the plausible viewpoints on climate change. Even so, he may well be correct. 350 is the number in parts per million that Hansen thinks we need to return to in order to keep the negative feed-backing mechanisms from getting out of control. Less than a decade ago he had considered 450 to be more of a tipping point (more in line with IPCC numbers) but recent data such as the increase in summer and overall melting of the Greenland ice sheets and knowledge of the slowness of the ocean to warm up (which means more effects of past greenhouse gas increases have yet to be seen) have led him to revise down to 350. The latest measure is around 395 ppm so we are well past 350 and still climbing worldwide.

Hansen suggests a kind of “disconnect” between scientists, most of which are seriously concerned with global warming and its potential impacts based on their own data, and politicians, especially in light of the special interests which inform them. He thinks the public is not getting a clear picture of the urgency of the situation. I think one problem is that humans are not habituated to projecting so far into the future at long-term goals, even if necessary, especially in such a situation where many sacrifices will need to be made.

One of he and Bill McKibben’s conclusions is that most or all fossil fuels need to be left in the ground – the sooner the better. Unfortunately, there is no clear alternative here that could pick up the slack in any reasonable manner anytime soon. Hansen suggests that so-called next-generation nuclear power as a viable alternative but many people and scientists would very strongly disagree. Curiously, in their policy suggestions there is little grading of fossil fuels in terms of greenhouse gas emissions. Replacing coal-burning power plants with natural gas has already resulted in significant reductions in the U.S. with the capacity for much more. China is the fastest growing greenhouse gas emitter and has been building coal-burning power plants en masse. So too has Europe since nuclear power plants have been retired in the wake of the Fukishima Daiko disaster – which happened a few months after this book was published. China has many natural gas resources which could take the place of coal at half the emissions. Instead of suggesting things such as this in the short-term, he tends to lump all fossil fuels together – citing recent thoroughly debunked studies linking shale gas extraction through “fracking” with contaminated water and excessive methane leakage. He does think getting to 350 is possible but not with special interests and greenwashing in the way. The first thing to do, he says, is to phase out coal emissions, either through not burning them or capturing the carbon – capturing the carbon would make burning coal much more expensive. It should also be noted that capturing ghg emissions from a natural gas power plant would cheaper and faster than doing so for coal – so practically speaking – he means phasing out the burning of coal. Coal has double the ghg emissions as gas and way more pollutants and particulates.

Hansen gives the definition of ‘climate forcing’ as “an imposed perturbation on the planet’s energy balance that tends to alter global temperature.” This is measured in watts per square meter. An example would be a brighter sun increases temp or as we now know more CO2 in the atmosphere increases temp. This warming can increase droughts and forest fires. A warmer atmosphere also means more moisture in the atmosphere which can lead to stronger storms and flooding events.

“How much climate responds to a specified forcing – specifically, how much global temperature will change – is called “climate sensitivity.”

He gives an excellent graph of comparisons of the magnitudes of known climate forcings given in positive or negative watts per meter squared from a zero point. A few examples of negative forcings (those that decrease temp) are aerosol effects which can be droplets due to particulate pollution, volcanic eruptions, or cloud changes. Land cover can also be a negative forcing. Many of the positive forcings are partially man-made: CO2, N2O, CFCs, methane, black carbon aerosols (ie. soot), other man-made gases, volcanic eruptions, the sun’s radiation, and ozone.

The global warming situation became dire for Hansen in the late 1980’s. He also felt that politicians muted his warnings and gave them too much uncertainty. He met Al Gore in 1989 and found someone willing to listen and we know Gore’s influence on the subject. After that Hansen went back to science until meeting with Dick Cheney and others around 2001. 

Hansen gives an account of his early career where he studied the atmosphere of Venus, where, strangely enough, early atmospheric compositional changes led by CO2 feedbacked out of control to render the atmosphere poisonous to life even though it was too hot for life as we know it anyway.

He gives an account of his meetings with the Bush-Cheney administration’s Climate Task Force. Here he gives the details of what he reported to the group. One thing I find interesting and compelling about Hansen’s data and presentation is that he gives the various climate forcings and their uncertainties, but he confines the various uncertainties into ranges to show the extent of their effects. While other researchers have sought to point out the uncertainties as a reason to delay action, Hansen shows that most of the uncertainties fall within a definable range that also suggest a range of total climate sensitivity. The biggest uncertainty is probably aerosols, particularly those associated with clouds – as some scientists point out as proof of uncertainty of the models, but more will be revealed about these effects as time goes on and as more data is gathered and interpreted. This effect is also sometimes called “global dimming”.  He does point out that CO2 is the largest single climate forcing known thus far and anthropogenic CO2 has significantly added to that.

In his next meeting before that Climate Task Force he was invited along with climate change contrarian Richard Lindzen, a Harvard and MIT scientist that has been described by many as a formidable opponent. Lindzen thinks climate sensitivity is much less due to the effects of clouds and that temperature rise over the coming decades will be much less. I hope he is right but I suspect he is not. Most climate scientists disagree with his “iris theory’ and some think he tends to tell other contrarians what they want to hear. He and a few others think that scientists in general have been coerced by politics into accepting the more alarmist climate change predictions. Hansen questions his approach to the scientific method. Lindzen is probably quite convenient for politicians seeking to debunk prevailing climate science. Hansen debated Lindzen in 1998 and provides some points from the debate in an appendix. He makes some important criticisms of Lindzen’s data, motives, and tendency toward contrarianism.

Hansen details his presentations to the Bush administration and how they were handled. He noted one his papers where he emphasized other greenhouse gases such as methane, CFCs, black soot, and smog-creating compounds, which combined are nearly as dangerous as CO2. Apparently, the White House science folk used this to de-emphasize the importance of CO2 as a greenhouse gas as some environmentalists warned. This was the time when the US actively opposed the Kyoto Protocol and Hansen does note problems with the protocol so he seems understanding of that hesitation. He goes into some detail of these politics referring to some books about them: Censoring Science and It’s My Party Too.

Climate sensitivity and paleoclimate, he says, are two things everyone should endeavor to understand. He notes that in natural climate oscillations temperature change precedes CO2 change. Most scientists agree and that is actually bad news since as temps continue to rise, according to the models, more CO2 will be released due to warmer oceans and partly their subsequent decreased solubility. He seems immeasurably confident that another ice age is not possible as long as we are around to force climate:

“ – even though we hear geoscientists talk as if ice ages will occur again, it won’t happen – unless humans go extinct. Forces instigating ice ages, as we shall see, are so small and slow that a single chlorofluorocarbon factory would be more than sufficient to overcome any natural tendency toward an ice age. Ice sheets will not descend over North America and Europe again as long as we are around to stop them.”

While he may well be correct, that is a pretty damn bold statement that assumes no hidden variables or uncertainties, considering the fact that around 90% of the last 400,000 years have been ice age conditions. One can only hope that if we can stave off an ice age so easily that we can also stave off a global warming catastrophe with some sort of climate engineering, but thus far, an answer has not emerged.

Close examination of ice core data shows that it takes several centuries before CO2 levels rise as a result of temperature rises and this is thought to be due to the slowness of ocean circulation in heating up the oceans. He refers to this as global warming “in the pipeline.” Sea level rise is also a clear result of CO2 and temperature rises in the paleoclimate record.

Forcings cause climate change and feedbacks determine the magnitude of climate changes. Feedbacks may amplify or diminish temperature. Ice, water (oceans), and water vapor are the three biggest feedbacks – water vapor, a greenhouse gas, being the largest. Less certain feedbacks are clouds, dust, and other aerosols such as dimethyl sulfur (emitted by algae). Feedbacks have different speeds – water vapor reacts quickly to temperature while ice sheets respond more slowly (decades/centuries?).

One of Hansen’s key points is that climate models, though useful, will always have uncertainties (which can also be exploited by contrarians). He points out that the paleoclimate record strongly suggests climate sensitivity based on different speeds of feedbacks. He mentions Jule Charney’s fast-feedback sensitivity. Charney determined that climate sensitivity in a non-feedback earth in energy balance was 0.3 deg Celsius for each watt of forcing – this is based on Planck’s Law, where radiation of energy by a body is a function of temperature. Charney determined that doubling CO2 with all other variables constant would reduce Earth’s heat radiation to space by 4 watts due to the trapping of heat in the greenhouse effect. This would raise temp by 1.5-4.5 deg Celsius. (Earth in energy balance would change it 4 x 0.3 deg Celsius or 1.2 deg Celsius [from Planck’s law]). Hansen notes that slow feedbacks are recently being seen as faster than previously thought which is one reason for his urgency. Times of sea level stability indicate an Earth in energy balance. Hansen finds example from the paleclimate record that indicate a climate forcing of 4 watts would raise temps about 3 deg Celsius – just in the mid-range Charney predicted. So based on these examples he sees climate sensitivity as 3 deg Celsius for doubling CO2 (4 watts forcing) or 0.75 deg per watt of climate forcing.

“… restoring Earth’s energy balance is the fundamental requirement for stabilizing our climate.”

The key driver for climate sensitivity changes is solar insolation. This is caused by two effects. The first is cyclical changes in the tilt of the Earth’s axis over a 41,000 year period where it goes from 22.1 deg to 24.5 deg. This slight axial wobble is due to gravitational effects from the other planets, especially Jupiter and Saturn. The second insolation effect has to do with the eccentricity of the Earth’s orbit which varies by about 6%. This effect is more complicated. Both of these effects currently suggest an impending ice age but Hansen notes that just the opposite is happening – ice is melting – and this is because human activities have taken over climate forcing. By this logic, the burning of fossil fuels has staved off the impending ice age but now the problem is a runaway greenhouse effect.

Hansen talks about problems among scientists with confronting orthodoxy or contradicting authority. An example is a question asked to him – if we don’t know the total effects of aerosols why are we not studying them? Thermal and terrestrial radiation can be measured by an instrument called IRIS (Infrared Interferometer Spectrometer). Small particles – aerosols or cloud droplets scatter the light emitted by the sun and polarize it. This effect can be measured and gives much information about the particles’ size, shape, and index of refraction. Instruments can also determine aerosol composition. Another instrument called a polarimeter measures this reflected sunlight. Hansen failed to get these instruments on a satellite to measure long-term climate change effects of aerosols and how they change through time. He credits his own lack of tact for this failure to get the importance through the “reticence” of the scientists and politicians planning the satellite. He talks much about this “scientific reticence” and suggests that the importance of objective skepticism and caution in science may be working against us in this case:

“… a preference for immediate, over delayed, rewards may contribute to irrational reticence even among rational scientists.”

Along with climate feedbacks there is also climate inertia, which refers to slower feedbacks. Ocean surface temp heats up in response to greenhouse gases in a few decades but the full heating of the ocean will take several centuries. Ice sheets are slow to heat up and begin melting but once they do, they can accelerate. Ice sheet collapse and sea level rise of tens of feet is likely, says Hansen, if we continue to burn fossil fuels at current rates. Paleoclimate evidence shows that sea level rose over 3ft every 20-25 years about 14,000 years ago when the ice sheets were melting strongly. This continued for several centuries. Hansen notes that amplifying feedbacks often occur on shorter time scales than diminishing feedbacks so in a sense the accelerator is in a hurry and the braking is slow. This is one reason why Hansen sees more urgency than the IPCC. Melting ice and shifting of climatic zones is occurring more rapidly than anticipated. Hansen thinks IPCC data does not take into account the acceleration of ice sheet disintegration. Hansen notes that about 90% of Earth’s energy imbalance ends up in the ocean some of which later goes to help melt ice sheets. IPCC models predict that global warming causes increased winter snowfall which offsets melting but Hansen says the warming ocean is not taken into account. Hansen claims that ice sheet melting dynamics, including, ice streams, increased ice bergs, and other processes, were not factored into IPCC models. Human-made black soot aerosols (some possibly from Western U.S. forest fires as well so I hear) deposited by weather on the Greenland Ice Sheet – causing heat absorption due to their color were also not factored in. These are definite amplifying feedbacks. The paleoclimate graphs show change from glacial to inter-glacial conditions proceeding faster than the reverse which strongly suggests the influence of amplifying feedbacks on ice sheet disintegration.

Regarding net climate forcing, it should be noted that Hansen thinks aerosols offset global warming by about one third. Particulate pollution is a main source of aerosols so if some of that is cleaned up as is needed for health, the corresponding offsetting effect will go away leading to another slight increase in warming. But there is significant uncertainty in the overall cooling effect of aerosols. Whatever the overall effect, it could still be more global warming “in the pipeline”.

Since most of Earth’s energy imbalance ends up in the ocean, Hansen argues, the most important measurements are those of ocean temperature. There are issues with instrumentation bias in recording and resolving ocean temps which are different at different depths and where warm and cool waters mix so it may not be easy to get beyond a certain margin of error. He notes that Earth’s energy imbalance can only be pinpointed somewhere between 0.25 and 0.75 watts. His own models came to 0.75 watt and he thinks that increased aerosols may have skewed his own modeling since he assumed a stable aerosol model. Current increases in coal pollution in China would suggest that he is right since they have far less pollution control than those in the US. In light of this, he suggests that the energy imbalance of Earth may be about 0.5 watts per square meter.

Solar irradiance is another significant climate forcing and has been precisely monitored since the 1970’s. Apparently there are some uncertainties in solar variability and solar cycles but Hansen explains them and confines the forcing effects in a range from 0.2 to 0.4 watts – significantly less than anthropogenic CO2. He has done much work with comparing efficacies of various climate forcings and again he comes to the conclusion that human-made climate forcing far outweighs natural climate forcing. Humans alter the carbon cycle in two ways” burning of fossil fuels and deforestation – both of which have been increasing for some time. Coal use in China has increased the rate quickly after it slowed for a few decades. CO2 emission data from fossil fuel burning are probably accurate to within 10%, he says. If this is compared to measured CO2 in the atmosphere, one can calculate the change in carbon uptake by carbon sinks such as forested land masses.

Hansen next gets into the quagmire of policy – though he would have preferred to stay a scientist and has thought much of this decision even if warned against it by scientists, politicians, and special interests. He does think it is possible to stave off catastrophic global warming if we can stabilize CO2 emissions by the first quarter of this century and then begin dropping them. This would require implementation of energy infrastructure changes within the decade. Hansen mentions author and environmentalist Bill McKibben bugging him for a target number for CO2 emissions. He was thinking of calling it 450.org. While IPCC climate models predict this would be fine, Hansen gives a good argument that the target should be much lower – ie. 350 parts per million. His main concern is that ice sheets will disintegrate much faster than previously thought due to feedbacks.

Climatic zones are shifting northward as are plant and animal species – due to temperature rise. These species migrations have the potential to upset delicately balanced ecosystems. Rates have been suggested at 35 miles per decade southward. Hansen points out that the 5 mass extinctions known have all been associated with changes in atmospheric composition and climate. The event at the end of the Permian is thought to have exterminated 90% of all terrestrial and marine species. Volcanoes likely initiated this event, with noxious gases, and finally global warming finishing it off. The global warming may have been precipitated by release of methane hydrates, from frozen arctic tundra and ocean continental shelves. This would further amplify global warming and is a potential problem now with loss of tundra and ice sheets. He goes through the other mass extinctions: the end of the Cretaceous (the one that wiped out the dinosaurs) and especially the Paleocene-Eocene Thermal Maximum (PETM) which occurred 55 million years ago. This one is considered minor, with half of deep marine foraminifera species expiring but few terrestrial species, but there were vast species migrations poleward and big changes in body sizes of species. PETM warming is thought to be about the same as may occur next century but it occurred over several millennia as opposed to a few centuries.

Next he goes into ocean floor cores and how they give very good data for temperature conditions far beyond the times of ice cores as the age of the ice is limited. Oxygen isotope ratios in foraminifera yield this data. He goes into great detail about the implications of this data, showing for one that the sun is not that big of a climate forcing – due to earth cooling consistently over millions of years while the sun’s energy was increasing. The cooling trend in the Cenozoic was initiated by India colliding into Asia and building up the Himalaya mountains. This caused massive new rock to be exposed to weathering which acts as a carbon sink, thus decreasing CO2 and then temperature. He uses all this data to show that a CO2 level of 450 ppm would be exceedingly dangerous, lead to unstoppable ice sheet collapse, and sea level rise as much as 250 ft – though time scales are not known. He demonstrates that this natural climate forcing of India colliding with Asia was about 10,000 times less powerful than that of anthropogenic CO2. Oxygen isotopes in the sea cores indicate that a massive increase in light carbon (about 3000 gigatons) occurred in 2 bursts, each less than 1000 years in duration. The likely source was methane hydrates. The question is whether the release of these hydrates had an external trigger or was the result of a climate feedback. Other PETM-like events show similar light carbon releases thought to be methane hydrates and it is strongly suggested that climate feedback is the mechanism. Most of these methane hydrates likely came from the continental shelves due to temp increase and this is what could occur with current global warming. The cooling since the Cenozoic has loaded up methane hydrates in ice. They can release quickly though it takes many millennia fro them to reload. An interesting and sobering observation is that the natural recovery time from the excess carbon in the air and ocean from the PETM event was about 100,000 years. Carbon cycle models predict a similar recovery time. In comparing other greenhouse gases to CO2, he notes that it is CO2 that is the main ingredient, and mitigating other gases instead of CO2 would only help minimally in the short term. For instance, methane is a potent greenhouse gas for about a decade but then will oxidize to CO2 (not sure of volume comparisons here) and continue to warm things.

Hansen gives five reasons why atmospheric CO2 needs to get down to 350 ppm: 1) arctic sea ice has been melting faster than the models predicted; 2) mountain glaciers are disappearing all over the world; 3) the Greenland and West Antarctic ice sheets are losing vast amounts of mass each year and sea level is rising 3cm per decade. This suggests that current atmospheric CO2 is too high; 4) subtropical regions have expanded poleward by 4 deg latitude on avg. This too has been faster than predicted by the models. Expanded dry regions and greater fire frequency is another result; 5) Coral reefs are highly stressed, being affected by ocean acidification and increased temps due to increased CO2. Hansen sees a big gap between public perception of the climate situation and the scientific reality. He suggests that contrarians are given a big voice by the media, since the media likes to provide two sides to a story. He also suggests that contrarians are media savvy and aided by politicians and special interests.

Hansen thinks that with a phase-out of coal emissions we could peak at 425 ppm CO2 before mid-century and fall to 350 by the end of the century. Unfortunately, this is not happening around the world. The U.S. has retired many of the oldest and dirtiest coal-fired power plants with plans to close more. This has been due as much to low natural gas prices as to pollution abatement. Germany is building coal-burning power plants to make up for phasing out nuclear power. He gives some info on carbon capture and storage (CCS) also known as carbon sequestration. This certainly has potential to mitigate carbon emissions but it is expensive and there are geological constraints to the effectiveness of storage reservoirs. Hansen also criticizes the carbon offsets touted by the Kyoto protocol as being ineffective at reducing emissions as well as the Kyoto targets as being largely ignored. He says the Kyoto protocol has basically been a failure.

One issue that I disagree with is where Hansen (as well as the IPCC I think) says that only conventional oil and gas reserves should be developed, with unconventional reserves left in the ground. While I can agree that tar sands should be left alone, unconventional shale gas and oil can be extracted more efficiently and inexpensively than much of the conventional reserves and can be a boon to moving away from coal in the short-term. He notes that if coal emissions are stabilized and then dropped out, we may even be able to get to 350 ppm by mid century. This is one way to help get there. Greater efficiency, more renewables, less usage, and possibly an energy consumption tax, would also help. He notes the California system where the utility companies make more money by encouraging efficiency rather than by selling power. This may be a good model for the future where people are rewarded for saving energy rather than the utilities trying to sell as much power as they can.

China and India are taking over from the US as the highest emitters. Both rely predominantly on coal for electricity. Wind and solar are not yet up to the task, he acknowledges. And this is likely to be the case for quite some time.

Next he goes in detail through the possible benefits of developing “fast-breeder” nuclear reactors for carbon free energy. These would utilize most of the uranium, using less of it, and would produce less waste than current nuclear power. However, it is unclear whether the technology is even feasible. He suggests that nuclear power is much safer than the public perceives it to be though many would disagree. He references a 2008 book by Tom Brees called Prescription for a Small Planet in support of nuclear power. He does suggest that these 3^rd-generation nuclear power plants are ready to go now. He suggests that 4^th generation nuclear plants could deal with the waste from 3^rd generation nuclear plants. I have read other things that contradict this so I am not sure of the feasibility and the safety would be questioned. He tries to explain that it is much safer than coal, as pollution from coal may be directly responsible for hundreds of thousands or even millions of premature deaths per year. Hansen thinks we should at least develop a demo plant of 4^th generation nuclear power – one that does not require much uranium and can use it efficiently. He strongly criticizes the anti-nukes movement. Without fossil fuels, baseload power capacity would have to be made by renewables (not feasible) or nuclear. He suggests baseload as a tossup between coal and nuclear but again does not mention natural gas which has the ability to replace coal now. There are even very recent applications that combine solar with natural gas power plants.

Hansen’s plan for a global phaseout of fossil fuel emissions involves a price on carbon, a tax at the mine, the wellhead, or port of entry. His idea is that of a tax and dividend structure. The dividend is meant to encourage saving energy and to stem rampant consumerism. Improved efficiency assurances and standards would increase due to further cost incentives. Fuel efficiency standards, appliance efficiency standards, and building efficiency standards will all be necessary. He does point out the limitations of “cap-and-trade” vs. “fee-and-dividend”. He also notes the obvious, that a rising carbon price would make efficiency measures work better. He does make a good argument for the overall failure of the cap-and-trade approach. One problem with the carbon tax approach is that it would be best if different countries, ie. the biggest polluters, agree on a price. Otherwise, this ends up giving an economic disadvantage to those that adopt it vs. those that don’t. This is problematic also in terms of per capita pollution as well as historical pollution, in which the U.S has been the leader. The key, he says, to first implementation of a carbon tax is for the US and China to come to agreement about their fair “shares” of a tax. India and other countries should also follow and those that do not do enough may end up subject to export fees and such sanctions. This valuation and agreement between countries would likely be no easy task but is probably feasible in some way. He does note that both China and India have reason to be worried about global warming, especially sea level rise, since both countries have hundreds of millions of people living on vulnerable coasts.  

He does touch on population as a significant factor in energy demand and also notes the strong correlation between decreased fertility rates and education and women’s rights. Indeed, promotion and enforcement of women’s rights around the world may do quite a lot to reduce population growth.

Next, he examines the “Venus Syndrome” which is thought to be the runaway greenhouse effect that made a once water-rich Venus too hot. He suggests this could happen on Earth with an imbalance of 10-20 watts per square meter. He also examines the scenario of a “snowball Earth” where ice would continue to grow and again suggests that humans are in control of climate and could easily stop such a situation. He briefly discusses geo-engineering as a way to mitigate global warming, but concludes that cost would far exceed reducing emissions.

Hansen also compares scenarios of the Cenozoic and PETM warmings and atmospheric CO2 quantities, suggesting they were less than previously thought. His conclusion here is that climate sensitivity increases as the atmosphere warms – which strongly suggests the dominance of positive feedback mechanisms.

In his work with policy and inspiring younger folk he came up with his “Declaration of Stewardship” which suggests that young people work to” 1) phase out coal emissions, 2) promote a gradually rising price on carbon emissions, and 3) improve energy efficiencies by making them pay even better than they do now. He also mentions some of his own forays into civil disobedience regarding mountaintop removal for coal and some other cases where others protested. I personally think such things need to be carefully chosen as all polluting and ghg-emitting sources are not equivalent.

Storms may get more intense and more chaotic as the atmosphere continues to warm and take on more moisture. This makes more available “fuel” for storms. There is no doubt that storms can cause massive damage, especially with ocean flooding and winds from hurricanes, tornadoes, and superstorms.

He notes that the ocean, the ice sheets, and the methane hydrates, all provide inertia to the rapid increase of anthropogenic CO2 and subsequent heat. Once this inertia is overcome and these can feedback, we may be doomed. The question is how much can the system stand before it does so – at what ghg concentration will we be safe from these effects? Hansen is betting on 350 ppm. We are currently at about 396 ppm.

He says that three quantities that need to be watched are: 1) mass balance of West Antarctic and Greenland ice sheets including their ice shelves, 2) percentage of fossil fuel CO2 emissions that remain in the air (this has been at 56% for decades due to the ability of carbon sinks to keep it level), 3) changes in atmospheric methane which may indicate release of methane hydrates.

There are some great appendices in this book as well including a point by point comparison and rebuttal of Richard Linzen’s points in debate, a great chart of climate forcings, and a Q & A with Bill McKibben. Hansen notes in the interview that the IPCC considers ice sheet collapse to be a linear process in their models but Hansen believes such a system in collapse could accelerate rapidly.

The bottom line, he notes, is that we have a responsibility to future generations to deal with this problem now as best we can, so that it does not get out of hand. The data suggest that the tipping points are very near. The challenge is to get the government and special interests at a minimum to endorse and implement the strategies requested by a majority of scientists (ie. the IPCC) and preferably to do the same for Hansen’s scenario which has much empirical evidence to support it.