«DIRECT TESTIMONY OF JAMES E. HANSEN Q. Please state your name and business address. A. My name is James E. Hansen. My business address is 2880 ...»
2007) that even with generous estimates for undiscovered oil and gas reserves, CO2 never exceeds 450 ppm if coal use is phased out except at power plants that capture and sequester the CO2. Old technology coal-fired power plants must be replaced by 2050, but the pressure for doing so will mount as climate change and its consequences become more apparent, especially the consequences for China, India and Bangladesh.
Q. But CO2 is already 385 ppm and increasing about 2 ppm per year. Does not simple arithmetic say that we will pass 450 ppm within a few decades?
A. Yes, if we keep increasing fossil fuel CO2 emissions. But that is not a god-given fact.
Q. But even if emissions from coal use are reduced, today’s oil plus gas emissions exceed coal emissions. How can coal be so important?
A. Phasing out coal emissions will reduce the annual growth rate of atmospheric CO2. Today, and for the period of accurate CO2 data, the annual increase of CO2 in the air averages 57% of the fossil fuel emissions (Figure 36), despite the fact that we (the world) have not done a good job of limiting deforestation and we have not done a good job of encouraging agricultural practices that would sequester CO2 in the soil. If we reduce CO2 emissions from coal, the airborne fraction of CO2 will decrease in the near and medium term, so there would be a more than proportionate decrease of the annual growth in atmospheric CO2.
28 Q. But will not a decrease in emissions of CO2 from coal be offset by a continuing increase in emissions of CO2 from oil?
A. On the contrary, oil production is going to peak and CO2 emissions from oil will inevitably decline, if not now then surely within the next few decades. And there is considerable potential, via improved forestry and agricultural practices, to do much better at sequestering CO2 in soil and in forests, as opposed to the loss (emission) of CO2 from forests and soils in the past.
Q. But you admit that we are likely to pass the dangerous level of CO2. Is there anything that can be done in that case?
A. In the short-term we only have to reduce CO2 emissions by more than 57% for atmospheric CO2 to begin to decline (in the long run the reduction must be larger). However, there is at least one feasible way to draw CO2 from the atmosphere. As summarized in Figure 37, if biofuels were burned in power plants, with the CO2 captured and sequestered, atmospheric CO2 could be drawn down (Hansen 2007c). The growing vegetation would take in CO2 from fossil fuel-elevated atmospheric levels, and this CO2 would then be captured at the power plant. In effect, fossil fuel CO2 would be put back underground, where it had come from.
The biofuels should be extracted from natural grasses or other cellulosic fibers farmed in a way that promotes soil conservation and carbon storage in the soil. Such an approach contrasts with production of corn-based ethanol, which in net is ineffective at reducing atmospheric CO2.
Q. Rather than go to this trouble, can we not adapt to the impacts of climate change?
A. Yes, leaving aside the effects of large changes in regional climate extremes and the extermination of species, we could deal with a one meter rise of sea level by making a lake large enough to hold that much water. Two hundred meter dams at the locations indicated in Figure 38 could hold that much water. A large number of people would be displaced by this lake. It may require difficult negotiations with Canada. And if we allow ice sheets to disintegrate to the point of one meter sea level rise, we can be quite sure that another meter is on the way.
Q. Is there not a good place for another lake?
A. Yes, it would require higher dams (242 meters), but one meter of sea level could be stored in Russia (Figure 39). This also displaces a large number of people. And if we let the ice sheets go that far, there is probably two more meters of sea level on the way. There are no remaining geological candidates for storing that much water. So the historic coastal cities are sunk. It seems that the adaptation path is a lot like appeasement; it just gets you into deeper trouble.
Q. Well then, is there still time to avoid the climate problems?
A. Yes, there is still time (Figure 40). As shown above, we can just barely still avoid 450 ppm by phasing out coal use except at power plants that capture and sequester CO2. It requires an almost immediate moratorium on new coal-fired power plants in the West, and, within a decade later, a moratorium in the developing world.
Q. Isn’t this going to cause energy shortages and blackouts?
A. Not if we exploit the potentials in energy efficiency, renewable energies, nuclear power, or other energy sources that do not produce greenhouse gases. We are going to have to learn to do that someday anyhow, and it is an enormous economic advantage to us if we learn it sooner rather
Q. Why take the first step? Why not demand that China act at the same time?
A. I already mentioned the economic reason. In addition, we are responsible for the problem.
China has just passed us in current emissions, but the climate change is due to cumulative emissions, not current emissions (Hansen et al. 2007b). The United States is responsible for more than three times as much of cumulative CO2 emissions as any other country, and we will continue to be most responsible for decades. Even with China’s high current emissions, our per capita emissions are five times as great as China’s.
Q. Is there any evidence that such an approach would work?
A. Certainly. The prior global atmospheric threat, destruction of the ozone layer, was solved with just such an approach. When the science suggested that chlorofluorocarbons (CFCs) had the potential to destroy the stratospheric ozone layer, there was an immediate moratorium on building of more CFC factories. Consumers played a big role in reducing demand, and immediately annual CFC production stabilized (Figure 43). Later, when the Antarctic Ozone hole was discovered, the Montreal Protocol was adopted and later strengthened several times, phasing out production of these chemicals. A key aspect of this protocol was that developing countries should have an extra ten years to implement the phase-out, and they should be provided with technical assistance to achieve it.
The ozone story was a success story (Figure 44), as scientists transmitted a clear message, the media informed the public, the public responded in a positive way, and the United States government exercised strong leadership. Special interests, the chemical companies producing CFCs, denied the science for several years, but they cooperated once it become clear that they could make money producing substitute chemicals.
Q. Why has the global warming story not followed a similar path?
A. The blame can be spread around. I believe that we scientists have not done as good a job in making clear the threat to the planet and creation. Special interests have been extremely effective in casting doubt on the science. Moreover, they have managed to have a great impact on the media, demanding that the story be presented as “fair and balanced” even when the evidence became “clear and unambiguous”. I also infer, based on numerous observations, that special interests have had undue influence (exceeding the one person one vote concept) on governments, especially in Washington.
Although the responsibility can be spread widely (Figure 46), the consequences of our profligate use of resources will be borne primarily by young people, today’s children and grandchildren, and later generations.
Q. Are you saying that the blame belongs on past generations?
A. No. They can genuinely say “we did not know”. The blame will fall squarely on today’s adults, if we do not act. We can no longer feign ignorance. Scientific consensus has been reached. If we stay on the business-as-usual course that our energy departments take for granted, when climate events unfold in the future it is not likely that our children and grandchildren will look back on our generation with equanimity, nor should they. If we allow climate to deteriorate and
Q. I am the one asking questions. Is there still time?
A. There is still time (Figure 47). However, it is clear that Congress does not ‘get it’. They stand ready to set a goal of 60% reductions, 80%, 90%! Horse manure. Those are meaningless numbers, serving nothing but their campaign purposes. Before you cast a vote for a politician ask whether they will support actions that can actually solve the problem. Specifically, I suggest that you ask them whether they will support the Declaration of Stewardship (Figure 48).
The most important question, by far, is the moratorium on new coal-fired power plants in the United States and Europe, the places that have created the climate problem. Until we take that action, we have no basis for a successful discussion with China, India, and other developing countries.
Q. So you think that replacing some people in congress can solve the problem?
A. It is important to replace members of Congress who place the profits of special interests above the future of our children and grandchildren, but even with personnel changes I would not expect Congress to solve the climate crisis without more direct help from the public. Strong specific messages are needed. Rejection of a coal-fired power plant that does not capture CO2 is such a message.
Of course such an action then places obligations on various parties. Steps must be taken to promote greater energy efficiency and acquisition of alternative energy sources. These are challenges that can be met and that will yield benefits in the future.
Q. Do you see reason for optimism if such steps are taken?
A. Yes. CO2 is the main problem. Figure 49d shows that the growth of CH4 is falling below even the alternative scenario, far below all IPCC scenarios. Figure 49e shows that the growth of N2O is close to the alternative scenario and below most IPCC scenarios. Figure 49f shows that the growth of Montreal Protocol trace gases and other trace gases is falling below all IPCC scenarios and is approaching the alternative scenario. So the growth of the non-CO2 climate forcings is encouraging.
Indeed, if we look at the growth rate of the sum of all long-lived greenhouse gases (Figure 50), we see that is it falling between the IPCC scenarios and the alternative scenario.
The reason that the net forcing is higher than in the alternative scenario is that the actual CO2 growth rate has exceeded the growth rate for CO2 assumed in the alternative scenario. Actual recent CO2 increases have averaged close to 2 ppm per year, while the alternative scenario requires the growth rate of the late 1990s (1.7 ppm) to decline to ~1.3 ppm per year by mid century. (If it turns out that 1°C additional global warming is dangerous, then an even steeper decline may be needed.) Clearly a much more promising future than in IPCC business-as-usual scenarios is possible. The issue is CO2 and more specifically it is coal. It is still possible to get on the alternative scenario track, and even do better than that scenario, but only if coal emissions begin to decline. Once the CO2 emissions are in the air we cannot get them back – a large fraction will stay in the air more than 1000 years.
31 Q. Can you summarize the status of the matter?
A. Figures 51 and 52 are my summary and my personal observations, my personal opinion. The climate surely is approaching tipping points, with the potential for us to lose control of the consequences. A solution is feasible and the required actions would have many side benefits.
Opposition, it seems to me, stems primarily from short-term special financial interests, whose effective misinformation campaigns make the struggle to inform difficult.
This is a matter which should unite those of conservative and liberal bents. The core issue is one of generational inequity. Younger people can help by making clear that they recognize the difference between words and deeds. Stalling and misinformation may help keep short-term profits flowing, but the legacy that it leaves on the planet will not be erased or forgotten.
Q. Do you have any final comment for the Board?
A. Yes. I would like to express my gratitude to the State of Iowa, which has always been so generous in providing educational opportunities to its people, even as many graduates go on to careers in other states across the nation. I was extremely fortunate to be able to attend the University of Iowa, and especially to learn in the Department of Physics and Astronomy of Prof.
James Van Allen. I thank Bruce Johansen and Ines Horovitz for comments on this testimony, and Makiko Sato for technical scientific assistance and my wife Anniek for her tolerance of inordinate obsessions.
Q. Does this conclude your prepared Direct Testimony?
A. With the following References, Figures and captions, yes.
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