Page images
PDF
EPUB

Scientific-Technical Analyses of Impacts, Adaptations, and Mitigation of Climate Change

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small]
[merged small][ocr errors]
[blocks in formation]

1990

BI NINGICI HD IS92 BI NINGICI HD IS92 BI NINGICI HD IS92 BI NINGICI HDIS92
2025
2075

2050

[blocks in formation]

2100

CO2 Sequestered in Depleted Natural Gas Wells, etc.

BI = Biomass-Intensive Variant; NI = Nuclear-Intensive Variant; NGI = Natural Gas-Intensive Variant;
CI=Coal-Intensive Variant; HD = High-Demand Variant

Figure 6: Annual energy-related CO2 emissions for alternative LESS constructions, with comparison to the IPCC IS92a-f scenarios.

important role in reducing current emissions of CO2, CH, and NO and in enhancing carbon sinks. A number of measures could conserve and sequester substantial amounts of carbon (approximately 60-90 Gt C in the forestry sector alone) over the next 50 years. In the forestry sector, costs for conserving and sequestering carbon in biomass and soil are estimated to range widely but can be competitive with other mitigation options. Factors affecting costs include opportunity costs of land; initial costs of planting and establishment; costs of nurseries; the cost of annual maintenance and monitoring; and transaction costs. Direct and indirect benefits will vary with national circumstances and could offset the costs. Other practices in the agriculture sector could reduce emissions of other greenhouse gases such as CH, and N2O. Land use and management measures include:

[ocr errors][merged small][merged small][ocr errors][merged small][ocr errors][merged small]
[ocr errors]

Promoting agroforestry

[ocr errors][ocr errors]
[ocr errors][ocr errors][merged small]

The net amount of carbon per unit area conserved or sequestered in living biomass under a particular forest management practice and present climate is relatively well understood. The most important uncertainties associated with estimating a global value are (i) the amount of land suitable and available for forestation, regeneration, and/or restoration programs; (ii) the rate at which tropical deforestation can actually be reduced; (iii) the long-term use (security) of these lands; and (iv) the continued suitability of some practices for particular locations given the possibility of changes in temperature, water availability, and so forth under climate change.

[blocks in formation]

Cross-sectoral assessment of different combinations of mitiga

Altering management of agricultural soils and rangelands tion options focuses on the interactions of the full range of tech-
Improving efficiency of fertilizer use

nologies and practices that are potentially capable of reducing

18

Scientific-Technical Analyses of Impacts, Adaptations, and Mitigation of Climate Change

emissions of greenhouse gases or sequestering carbon. Current analysis suggests the following:

4.4.

Competing Uses of Land, Water, and Other Natural Resources. A growing population and expanding economy will increase the demand for land and other natural resources needed to provide, inter alia, food, fiber, forest products, and recreation services. Climate change will interact with the resulting intensified patterns of resource use. Land and other resources could also be required for mitigation of greenhouse gas emissions. Agricultural productivity improvements throughout the world and especially in developing countries would increase availability of land for production of biomass energy.

Geoengineering Options. Some geoengineering approaches to counterbalance greenhouse gas-induced climate change have been suggested (e.g., putting solar radiation reflectors in space or injecting sulfate aerosols into the atmosphere to mimic the cooling influence of volcanic eruptions). Such approaches generally are likely to be ineffective, expensive to sustain, and/or to have serious environmental and other effects that are in many cases poorly understood.

Policy Instruments

Mitigation depends on reducing barriers to the diffusion and transfer of technology, mobilizing financial resources, supporting capacity building in developing countries, and other approaches to assist in the implementation of behavioral changes and technological opportunities in all regions of the globe. The optimum mix of policies will vary from country to country, depending upon political structure and societal receptiveness. The leadership of national governments in applying these policies will contribute to responding to adverse consequences of climate change. Governments can choose policies that facilitate the penetration of less greenhouse gas-intensive technologies and modified consumption patterns. Indeed, many countries have extensive experience with a variety of policies that can accelerate the adoption of such technologies. This experience comes from efforts over the past 20 to 30 years to achieve improved energy efficiency, reduce the environmental impacts of agricultural policies, and meet conservation and environmental goals unrelated to climate change. Policies to reduce net greenhouse gas emissions appear more easily implemented when they are designed to address other concerns that impede sustainable development (e.g., air pollution and soil erosion). A number of policies, some of which may need regional or international agreement, can facilitate the penetration of less greenhouse gas-intensive technologies and modified consumption patterns, including:

Putting in place appropriate institutional and structural frameworks

Energy pricing strategies (e.g., carbon or energy

[ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors]

Reducing or removing other subsidies (e.g., agricultural and transport subsidies) that increase greenhouse gas emissions

Tradable emissions permits

Voluntary programs and negotiated agreements with industry

Utility demand-side management programs

Regulatory programs, including minimum energyefficiency standards (e.g., for appliances and fuel economy)

Stimulating RD&D to make new technologies available Market pull and demonstration programs that stimulate the development and application of advanced technologies

Renewable energy incentives during market build-up Incentives such as provisions for accelerated depreciation and reduced costs for consumers

Education and training; information and advisory

measures

Options that also support other economic and environmental goals.

Accelerated development of technologies that will reduce greenhouse gas emissions and enhance greenhouse gas sinksas well as understanding the barriers that inhibit their diffusion into the marketplace-requires intensified research and development by governments and the private sector.

Authors/Reviewers

Robert T. Watson, USA; M.C. Zinyowera, Zimbabwe, Richard H. Moss, USA; Roberto Acosta Moreno, Cuba; Sharad P. Adhikary, Nepal; Michael Adler, USA; Shardul Agrawala, India; Adrian Guillermo Aguilar, Mexico; Saiyed Al-Khouli, Saudi Arabia Barbara Allen-Diaz, USA; B. W. Ang. Singapore, Anne Arquit-Niederberger, Switzerland; Walter Baethgen, Uruguay, Martin Beniston, Switzerland, Luitzen Bijlsma, The Netherlands; Rosina Bierbaum, USA; Michel Boko, Republic of Benin, Bert Bolin, Sweden; Sandra Brown, USA; Peter Bullock, UK; Melvin G.R. Cannell, UK; Osvaldo F.

Canziani, Argentina; Rodolfo Carcavallo, Argentina, William Chandler, USA; Fred C.

Cheghe, Kenya. Vernon Cole, USA. Rex Victor Cruz, Philippines: Ogunlade Davidson,

Sierra Leone; Sandra Diaz, Argentina; Andrew F. Dlugolecki, Scotland; James A Edmonds, USA; Lin Erda, China; John Everett, USA: Zhou Fengqi, China; Andreas Fischlin, Switzerland, B. Blair Fitzharris, New Zealand; Douglas G. Fox, USA; Jaafar Friaa, Tunisia, Alexander Rauja Gacuhi, Kenya; W. Galinski, Poland, Habiba Gitay, Australia; Howard Gruenspecht, USA: Steven P. Hamburg, USA; Hisashi Ishitani, Japan; Venugopalan Ittekkot, Germany. Thomas B. Johansson, Sweden; Zdzisław Kaczmarek, Poland, Takao Kashiwagi, Japan; Miko Kirschbaum, Australia; Andrei Krovnin, Russian Federation; Richard J.T. Klein, The Netherlands, S.M. Kulshrestha, India; Herbert Lang, Switzerland; Henry Le Houerou, France; Rik Leemans, The Netherlands; Mark D. Levine, USA; Chunzhen Liu, China; Daniel Lluch-Belda, Mexico; Michael MacCracken, USA; Gabriel M. Mailu, Kenya, Kathy Maskell, UK; Roger F. McLean, Australia, Anthony J. McMichael, UK; Laurie Michaelis, France, Ed Miles, USA; William Moomaw, USA; Roberto Moreira, Brazil; Nebojsa Nakioenovic, Austria: Shuzo Nishioka, Japan; lan Noble, Australia; Leonard A. Nurse, Barbados; Rispa Odongo, Kenya; Mats Oquist, Sweden; Martin L. Parry, UK; Martha Perdomo, Venezuela: Michel Petit, France, P.S. Ramakrishnan, India; N.H. Ravindranath, India, John Reilly, USA: Arthur Riedacker, France; Hans-Holger Rogner, Canada; Jayant Sathaye, USA; Michael J. Scott, USA: Subodh K. Sharma, India; David Shriner, USA; S.K. Sinha, India; Jim F. Skea, UK; Allen M. Solomon, USA; Eugene Z. Stakhiv, USA; Oedon Starosolszky, Hungary, Su Jilan, China; Avelino Suarez, Cuba; Bo Svensson, Sweden; Hidekazu Takakura, Japan; Melissa Taylor, USA; Dennis Tirpak, USA; Viet Lien Tran, Vietnam; Jean-Paul Troadec, France, Hiroshi Tsukamoto, Japan; Itsuya Tsuzaka, Japan; Pier Vellings. The Netherlands; Ted Williams, USA; Youyu Xie, China; Deying Xu, China; Patrick Young, USA

Mr. ROHRABACHER. Just a point of clarification before we move on there to Dr. Nierenberg.

You mentioned what would happen in these various countries if, you said, there was a one meter rise in the ocean?

Are you projecting, or is someone projecting that there is going to be a one-meter rise in the ocean level?

Dr. WATSON. The IPCC Working Group I is projecting that by the year 2100 temperature would be 1 to 3.5 degrees centigrade warmer, and therefore sea level would be between 15 centimeters and 95 centimeters. In other words, within 5 centimeters of 1 meter by 2100.

But even then, even larger changes thereafter, even if we stabilize climate, in the year 2100 sea level would continue to increase for another couple of centuries.

So the answer is, yes, it is within the feasible range of our projections.

Mr. ROHRABACHER. So in 100 years, you are not predicting the 1 meter, but you say that after that it could well continue to rise? Dr. WATSON. Our best estimate is 50 centimeters in one century, although it is not implausible it could also be one meter. Thereafter, there is no question it could continue to rise to 1 meter and greater.

Mr. ROHRABACHER. Okay. We will get back to that a little later. Dr. Nierenberg?

STATEMENT OF WILLIAM A. NIERENBERG, DIRECTOR EMERITUS, SCRIPPS INSTITUTE OF OCEANOGRAPHY Mr. NIERENBERG. Mr. Chairman, I am grateful for this opportunity to place my views on climate change and modelling before the committee. The testimony is based largely on two documentsProgress and Problems. A Decade of Research on Global Warming, The Bridge, (National Academy of Engineering); and Looking Back Ten Years, a publication at IIASA. I hope these can go into the record, Mr. Chairman.

Mr. ROHRABACHER. It is so ordered, with no objection.

Mr. NIERENBERG. I begin by repeating what I often feel is a necessary prelude to a presentation of the issues. There is no question in my mind that the current anthropological growth of CO2 in the atmosphere ins bound to influence the climate. The question is not whether but when, how much, and the nature and the magnitude of the effects.

The fixing of when has taken an interesting turn. Ten years ago, discussion of effects centered around the middle of next century, often the year 2040. Now, almost universally, climate change effects are normalized at the year 2100, 105 years away from the present.

As an example and I have to differ-an average sea level rise is projected by current models to be about 30 centimeters, 1 foot, at that time, by the year 2100.

This rate also seems to be consistent with the early returns from the TOPEX satellite measurements.

I should be wanting in this recital if I did not direct your attention to the large difference between this result and earlier predictions of an order of magnitude larger changes.

It was only 15 years ago that a leading scientist predicted 25 feet in decades. We now have 1 foot in 105 years.

The number that surfaces most often in the discussion of climate is the change in the average global surface temperature change. The data for the past 100 years has been painfully and methodically pieced together and shows a rise of about 0.6 degrees Centigrade.

Unfortunately—I hate to read the rest of this paragraph, because Congressman Ehlers preempted my remark at this point-unfortunately, this is the least interesting aspect of climate change.

What is crucial is knowledge of the change in the statistical behavior and by that I do not mean the average; I mean the sigma, the root mean square variation of the quantity such as rainfall, storm frequency and intensity, flooding, coastal storm surges, and

so on.

By contrast, we can visualize an induced change that increases cloud coverage to the extent that the temperature rises very little, but clearly this is a definite climate change.

The weaknesses of the models is most clearly demonstrated by the historical observation that, since the original Charney report of the NRC in 1978, the National Academy of Sciences report of 1983, the IPCC report of 1990 and today, the spread of the temperature rise between the 15 or so climate models worldwide remains-it has not changed at all-between 1.5 to 4.5 degrees centigrade. It is correct. The previous speaker has knocked a half a degree off both limits-for an anticipated doubling of the atmospheric CO2.

This variation between the models is also reflected in lack of agreement in many of the predicted regional changes which are so important.

You have heard-and I am repeating-that the primary reason for these disagreements is the poorly represented internal radiation transfer properties and the overall effect of water in clouds, cloud formation, and water vapor.

This is in recognition that water in the form of clouds and vapor is the primary greenhouse gas. CO2 is not. Its changes, however, indirectly affect the water via feedback effects.

This has been recognized for years, going back at least to the 1983 NAS report, but it is only recently that serious field programs have been undertaken to formulate a better parameterization of these phenomena. The ARM and CHAMPP programs are in this category.

The other element of time that is crucial and has been mentioned several times is the lifetime of the excess anthropogenic CO2 in the atmosphere. This is a most important number-it is the most important number for policy considerations.

Here the advent of the coupled ocean-atmosphere model has made definite impact. What is being discussed here is how quickly would the atmosphere relax to a steady state or even its original unimpacted states if the anthropological impact of CO2 was severely reduced or even curtailed.

The base assumption is that, one way or another, fossil fuel reserves will be exhausted in several hundred years leading to a cutoff in the injection of CO2 into the atmosphere.

At the time of the 1983 report, the then-current calculation in the literature proposed a behavior based on a 1000-year exponential lifetime for the disappearance of the excess CO2 in the atmosphere. That is, that that concentration would be reduced by one-third each thousand years thereafter.

This meant that, even if the flow of CO2 were cut off, the climate effects, for better or worse, would persist for that length of time. It is even worse. It would mean that modest reductions in emission rates would have negligible effects on the peak value of the perturbation—although it would delay its onset.

It would take a massive change in emissions to have an appreciable effect. This creates a policy situation that is almost a crisis one in that any climate change must be treated as hostile even in the absence of specific knowledge and the ability to make accurate climate predictions.

The coupled ocean-atmosphere model has given us better insight into the mechanism of this decay and has greatly reduced its value. For today, we can take it as ranging between 50 and 160 years.

The actual choice is a complicated one. It is an approximation to the true time variation depending on how long is the extent and the shape of the emission curve.

At any rate, it is a big change from the prior 1000-year value and complete alters the policy picture.

Mr. ROHRABACHER. Dr. Nierenberg, would you summarize?

Mr. NIERENBERG. Yes, just one more paragraph just to make this point. Well, this is my main point.

It is to be interpreted in either of two ways, or a combination of both.

On the one hand, those who feel that corrective measures must be taken immediately can now take comfort in the fact that any reasonably applied change in emissions would be reflected in a proportionate reduction in the peak CO2 concentration.

On the other, those who take the more conservative view may argue that one can now safely wait until the climate changes become clearer and more definitely negative before taking action. since the effect of the mitigating action would show up in reasonable time.

Thank you.

[The prepared statement and attachments of Mr. Nierenberg follow:]

PREPARED STATEMENT OF WILLIAM A. NIERENBERG, DIRECTOR EMERITUS, SCRIPPS INSTITUTION OF OCEANOGRAPHY

I am grateful for this opportunity to place my views on climate change and modelling before the committee. This testimony is based largely on two documentsProgress and Problems: A Decade of Research on Global Warming, The Bridge (NAE), Vol. 25, No. 2 Summer 1995, pp4-9 and Looking Back Ten Years, IIASA Proceedings, CP-94-9, which I put on the record.

In this prepared statement I summarize what I have written but I do include some additional results that have become available since their publication.

I begin by repeating what I often feel is a necessary prelude to a presentation of the issues. There is no question in my mind that the current anthropological growth of CO2 in the atmosphere is bound to influence the climate. The question is not whether but when, how much and the nature and magnitude of the effects.

The fixing of when has taken an interesting turn. Ten years ago discussions of effects centered around the middle of the next century, often the year 2040. Now, almost universally, climate change effects are normalized at the year 2100, 105

« PreviousContinue »