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Aiming for equity

Daniel Kammen and Ann Kinzig discuss strategies for reducing greenhouse gas emissions substantially, with equity to the fore.

Daniel M Kammen is Associate Professor of Energy and Society in the Energy and Resources Group at the University of California, Berkeley, in the United States. He also directs the Renewable and Appropriate Energy Laboratory.

Ann P Kinzig is Assistant Professor of Urban Ecology in the Department of Biology, Arizona State University, Tempe, Arizona, United States. She is currently on leave serving as the first Roger Revelle Fellow in Global Stewardship in Washington, DC.

The Fourth Conference of the Parties (COP4) to the United Nations Framework Convention on Climate Change (UNFCCC) will be held from November 2nd-13th 1998 in Buenos Aires, Argentina.

COP4 provides an important opportunity to move toward ratification of the Kyoto Protocol on climate change. The Protocol calls for an overall five per cent cut in greenhouse gas emissions from industrial nations by 2010 — it will also be necessary to begin developing mechanisms to reduce global greenhouse gas emissions more substantially.

Ratification of the Kyoto agreement is an important beginning, but clearly must be part of a longer-term plan of emission reductions and a transition to a clean, low-carbon economy. A combination of research and development, and technological and political innovations, will be required to meet this challenge.

In this article, we analyse the likely trajectory of national greenhouse gas emissions and outline a proposal to meet and move beyond the Kyoto agreement. A robust result of our analysis is that early action by both developed and developing nations is required to stabilize atmospheric concentrations of carbon dioxide at or below doubled pre-industrial levels. To meet this goal, emissions would eventually need to be limited to 2 to 3 Gt C per year (109 metric tonnes of carbon per year), significantly below the current level of about 6 Gt C per year.

We also argue that, in the long term, global equity in per person emission rights is not only ethically the most reasonable target, but is also the least cumbersome basis for an international agreement.

Atmospheric carbon dioxide concentrations

The UNFCCC calls for limiting greenhouse gas concentrations in the atmosphere to a “level that would prevent dangerous anthropogenic interference with the climate system.” A consensus is developing among many scientists, however, that even a doubling of carbon dioxide concentrations from the pre-industrial levels of about 280 ppmv (parts per million by volume) could have far-reaching impacts.

According to the Intergovernmental Panel on Climate Change (IPCC), stabilizing atmospheric carbon dioxide concentrations at close to twice the pre-industrial level would still commit the world to global warming of 1 to 2 degrees Celsius and a significant rise in sea level, with consequent impacts on ecosystems and human welfare. The potential for catastrophic events such as a reduction in the oceanic thermohaline circulation or the collapse of large portions of the Antarctic ice sheets would also increase.

The analyses presented here are, therefore, aimed at limiting the maximum atmospheric concentration of carbon dioxide to roughly 450 ppmv, short of a doubling of atmospheric carbon dioxide. In a longer account of this study (see box on page 7), we also explore scenarios leading to concentrations of 550 ppmv.

Following the IPCC, stabilizing atmospheric carbon dioxide concentrations at 450 ppmv requires constraining global cumulative emissions between 1990 and 2100 to about 630 Gt C (630 x 109 metric tonnes of carbon). These cumulative emissions would include contributions from fossil-fuel burning, cement production, non-renewable uses of forest products, and other biospheric emissions.

In the future, the terrestrial biosphere is expected to release carbon as forests are negatively affected by changes in climate or land conversion for agricultural and other activities. This forest dieback or degradation could potentially contribute 10 to 100 Gt C to the atmosphere in the coming century.

We assume that industrial carbon dioxide emissions need to be limited to at most 600 Gt C between 1990 and 2100 if concentrations are to be held to 450 ppmv. This corresponds to annual emissions of about 2 Gt C per year by the end of the next century, according to the IPCC. In contrast, current global industrial emissions are now about 6 Gt C per year, and growing by 4.6 per cent a year in developing nations and 1 per cent in developed nations. Under a “Business-As-Usual” scenario, global cumulative emissions between 1990 and 2100 would be well in excess of 1500 Gt C, and annual emissions could stand at over 20 Gt C per year by the end of the next century.

Reformulating the global economy to operate with an annual carbon emissions budget of 2 to 3 Gt C will unquestionably require innovation, cooperation and incentives for both public and private sector institutions.

We share the view expressed by Masood, writing in the journal Nature, that compelling political, institutional and moral arguments exist to warrant the goal of equity where individuals have equal rights to the carbon capacity of the atmosphere.

The United Nations forecasts that the global population in 2050 is likely to be 10 billion. Based on the 2 Gt C per year emissions limit required to stabilize atmospheric carbon dioxide to 450 ppmv, this population projection leads to a per capita cap of 0.2 tonnes/person/year. All developed nations and many developing nations already exceed this total. The transition from the current distribution to an equitable one will require some time.

We envision an international emissions regime that:

  • in the long-term, recognizes the equal rights of people to exploit the services of the atmosphere and pursue a reasonable standard of living in a low-carbon economy;
  • in the near- and medium-term, addresses the inequities resulting from historic imbalances in emissions while promoting efficient pathways for carbon reduction; and,
  • in the short-term, “jump starts” the process by providing incentives to exploit profitable or low-cost carbon reduction opportunities.

A simple model for analysing emissions and reductions scenarios

To examine likely future emissions, we divide all nations into four Annex categories. The Annex I and I(a) nations are as defined in the UNFCCC to include the industrialized nations (Annex I) and the former centrally planned economies (Annex I(a)). We categorize the remaining nations based on the long-term “permissible emissions” level of 0.2 tonnes C per person per year. Annex III nations are those developing nations whose current emissions exceed future permissible levels; Annex IV nations are currently below their long-term permitted emissions levels.



Current (1994) emissions
(000 tonnes C per year)

Medium UN population forecast for 2050

Long-term emissions targets
(000 tonnes C per year)

Current emissions/ Long-term targets

United States


















United Kingdom






























Costa Rica
























Representative national emissions totals, population forecasts and long-term limits.

To put these numbers in perspective, the table above shows current emissions and required cuts for a representative set of nations for a total population of roughly 10 billion. The final column shows how far a representative set of nations are over (or under) the 0.2 tonnes cap. While the United States and many industrialized nations are 10 to 20 times over their long-term target, even Brazil and China are already over their target. Bangladesh would be permitted to increase emissions 10-fold and Sudan could increase them 20-fold.

In our analysis, Annex I and I(a) nations are presumed to be committed to the Kyoto Protocol which will result in emissions in 2010 five per cent below 1990 levels. The magnitude of the carbon reductions each year are assumed to vary logistically: that is, initial carbon reductions are small, but increase as policies, markets, and technologies adjust to the requirements of the convention. After a time, annual carbon reductions again diminish as the most promising and inexpensive carbon-reduction opportunities are exploited. This reductions trajectory is consistent with the calls for a “slow start” in reductions commitments.

Emissions from Annex III and IV nations are assumed to continue to grow exponentially prior to the onset of actions to comply with the climate treaty. Once reductions for these nations begin, the same assumptions are made as for Annex I and I(a) nations.


We examined a variety of emissions scenarios to determine the qualitative impact of early carbon mitigation actions undertaken by Annex I-IV nations, and to evaluate the excess cumulative emissions resulting from delayed action.

Three industrial emissions trajectories were analysed for Annex I nations: Slow (S), Moderate (M), and Aggressive (A). Similarly, three industrial emissions trajectories were analysed for Annex III and IV nations: Delayed (D), Early (E), and Immediate (I). Our Slow scenario for the Annex I nations corresponds roughly to the Kyoto Protocol.

The emissions trajectories are as follows:

Slow Annex I reductions (S): Annex I and I(a) nations reach 95 per cent of 1990 emissions by 2010, and reach long-term emissions limits of 0.2 tonnes C per person per year by 2100.

Moderate Annex I reductions (M): Annex I and I(a) nations reach 90 per cent of 1990 emissions by 2010, and complete the transition to long-term emissions limits by 2075.

Aggressive Annex I reductions (A): Annex I and I(a) nations reach 85 per cent of 1990 emissions by 2010, and complete the transition to long-term emissions limits by 2050.

Delayed Annex III and IV reductions (D): Annex III and IV industrial emissions grow until 2020 at 4.6 per cent and 6.2 per cent per year, respectively, at which time emissions reductions begin. Long-term emissions limits are reached in 80 years, by 2100.

Early Annex III and IV reductions (E): Annex III nations begin emissions reductions in 2010 (with growth prior to that time), reaching long-term limits within a century, by 2110. Annex IV nations continue growth until 2010 at which time emissions first exceed the long-term permissible levels. Gradual declines in emissions then ensue and Annex IV nations reach long-term permissible levels 100 years later.

Immediate Annex III reductions (I): Annex III nations begin emissions reductions in 2000 (with growth prior to that time), reaching long-term limits within a century, by 2100. Annex IV nations continue growth until 2010 at which time emissions first exceed the long-term permissible levels. Gradual declines in emissions then ensue, and Annex IV nations reach long-term permissible levels 100 years later.

These emissions trajectories were combined in pairs to form five scenarios: SD, AD, MD, ME, and MI. The first letter in each scenario gives the emissions trajectory for Annex I and I(a) nations, with the second letter giving emissions trajectories for Annex III and IV nations. Thus the MD scenario is one in which Annex I nations follow a moderate reductions trajectory while Annex III and IV nations delay reductions. The MD scenario was taken as a “base case” scenario against which to compare Annex I and Annex III-IV actions.


In all of the scenarios where developing nations delay action until 2020 (SD, AD, and MD) — whether there is aggressive action from Annex I nations or not — cumulative emissions are significantly in excess of our 600 Gt C target (see Figure below). Speeding the transition by allowing less than a century to reach long-term emissions goals (MD) is not a substitute for early action. It is only when there are early activities in developing nations towards reducing emissions that it is possible to confine carbon dioxide levels to those consistent with stabilizing concentrations at 450 ppmv.

Cumulative emissions under the five scenarios for the 450 ppmv concentration target. Solid line: 600 Gt C cumulative emissions target, assuming a 30 Gt C release from the biosphere over 1990-2100. Upper and lower dotted lines: range of uncertainty in the cumulative emissions target, 630 to 530 Gt C, dependent on range in biosphere releases of 0 to 100 Gt C.

The developing nations of the world have argued — with some legitimacy — that the Annex I nations must be the first to significantly cut carbon dioxide emissions, while the developing nations continue to spur their economic development with inexpensive and abundant fossil-fuel energy resources.

The resulting emissions totals in our scenarios show the difficulty of this stance. Action on the part of both Annex I and Annex III-IV nations is required within the next decade (ME scenario); such early action increases the probability of success while decreasing the speed with which the ultimate transition to a low-carbon economy must be made.

Many developing nations are extremely vulnerable to the impacts of global climate change — because many have low-lying coastal areas, many have either marginal agricultural surpluses or are currently unable to feed their populations, and a greater proportion of their citizens find themselves in fragile or precarious economic and ecological circumstances. Arguing that only the developed nations should act in the near term — when such action will not be sufficient to avoid potential catastrophes — is akin to arguing about the placement of the deck chairs on the Titanic. Who will sit in the bow and who in the stern as the ship sinks?

At the same time, developed nations of the world cannot insulate themselves from global events and catastrophes, and their past behaviour in coopting more than their share of the environmental services provided by the atmosphere, along with the superior economic position that resulted from this allocation of atmospheric resources, suggests that they must bear a significant fraction of the financial burden involved in procuring early participation of developing nations in a climate convention.

The scenarios presented in this section are consistent with initial action on the part of Annex I and I(a) nations; reductions commitments in Annex III and IV nations could follow about a decade behind, as long as industrialized nations commit to emissions reductions soon.

In the next section, we propose a policy consistent with incentives for early participation by Annex III-IV nations and greater financial responsibility from Annex I and I(a) nations.

Jump-starting the process

The global effort to mitigate climate change requires a diversity of policy interventions. We concentrate on a modified and revitalized Joint Implementation (JI) proposal here because it results in immediate action to reduce the current and future emission of greenhouse gases and because it builds the scientific and political infrastructure needed to implement a full climate convention.

It is important to note, however, that many developing countries have expressed the legitimate concern that JI merely allows the Annex I nations to abuse the spirit of an international greenhouse gas convention or treaty, by focusing their efforts predominantly on JI to the exclusion of the unavoidable need to reduce domestic emissions (and thus to address some basic domestic economic issues, and potential accompanying costs).

The proposal we develop below is intended to augment current discussions, and should not be considered a replacement for other essential aspects of a climate agreement, such as a multilateral fund for developing nations and expanded commitments of Annex I signatories to provide assistance packages beyond the JI programme. To this end, the Swiss proposal to limit to JI to, for example, 50 per cent of total reduction obligations for Annex I nations must be a central tenet of any agreement.

Our proposal is that:

A framework should be established whereby bilateral accords are recorded and assessed for their role in carbon mitigation or sequestration. These credits will be “banked” for use when an accord is ratified. Initially, both nations will receive full credit for avoided or mitigated carbon emissions. This “double counting” can be phased out over time, providing a further impetus for early action. Credits will have finite lifetimes, with longer expiration periods for the developing-nation partner than the developed-nation partner (to account for the fact that full less developed country participation in a convention will be delayed relative to Annex I participation).

This simple proposal addresses a variety of obstacles to implementing significant positive steps to alter the current carbon-intensive world economy. The plan immediately implements a no-regrets, or at least minimum-regrets, policy to reduce anthropogenic greenhouse warming, as well as initiating a process that forces all nations to grapple with questions of the carbon “content” of mitigation projects, the issues of monitoring and accounting, and the long-term efficiency of actual projects compared to the theoretical yields promised today.

By rewarding early action and cooperation this proposal also resolves a number of potential problems.

Problem: JI agreements will not be explored widely and implemented until a greenhouse gas treaty is ratified, which may not take place for some time. This problem of inaction reduces policy options and increases costs once a regime is finally adopted because of the resulting magnitude of the problem and the long atmospheric lifetime of greenhouse gases already emitted. Moreover, low-cost, and even some negative cost, greenhouse gas reduction options exist, but nations are reluctant to exploit even these options prior to a convention which may not recognize past actions.

Problem: Developing nations have been reluctant to embrace JI for fear that developed nations would “skim the cream” in developing nations, exploiting the cheapest and most tractable carbon-reduction opportunities and leaving the developing nations with more difficult and costly tasks when their own obligations for emissions reductions begin.

Problem: Difficult questions exist as to how credit for JI programmes should be divided. A limited programme lifetime, however, means that nations may receive credit for reductions in carbon emissions for perhaps a decade’s worth of avoided emissions by building a low-carbon power plant with a lifetime of 40 years. There is then little harm in the double-counting because the potential additional emissions today will be more than compensated by emissions avoided in the future.

Problem: As with any technology or management policy, a learning curve exists that can only be overcome by implementing actual projects. The sooner significant project implementation can begin, the sooner additional innovations and more efficient project designs will be discovered.

Problem: Any agreement resulting from the Fourth Conference of the Parties in Buenos Aires in November 1998 will be complex, requiring new levels of global coordination and monitoring. But, if credit is given for projects initiated prior to the ratification of the full convention, a smaller infrastructure will be needed in advance to begin to perform monitoring and conduct scientific and policy assessments. In addition, monitoring and assessment of the actual greenhouse gas benefits of these early JI programmes encourages the development and standardization of new scientific methods and the collection of valuable information. This encourages important policy-relevant research. Further, as countries accrue credits the momentum will build to “cash them in” which is only possible if a climate convention is ratified.

The impacts of “double counting” credits

The near-term “double counting” of emissions credits might lead to some concern over the impact on total emissions. To analyse the impact of this double counting on total emissions, we extended our model to analyse a joint implementation regime.

Annex I and I(a) nations were committed to reductions in 2010 totalling 10 per cent of 1990 emissions (i.e. 2010 emissions equal to 90 per cent of 1990 emissions); half of those reduction requirements could be offset by JI so that the net effect was to reduce national emissions to about 95 per cent of 1990 levels. (Global emissions are still reduced consistent with total Annex I and I(a) commitments, with some reduction taking place in developing nations.) Thus, JI projects offsetting about 0.2 Gt C over the period 1995-2010 were assumed to be deployed in Annex III-IV nations.

JI projects were allocated in this scenario based on a share of total Annex III-IV emissions, on the assumption that current emissions are a reasonable measure of opportunities for reduction. (Annex IV nations, for instance, account for about 20 per cent of Annex III-IV emissions in the year 2000, qualifying them for 20 per cent of the JI projects in that year.) Developing nations had carbon dioxide emissions that were assumed to grow exponentially between 1995-2010 (minus the reductions that come from JI), and JI credits were “banked” until emissions reductions begin in 2010. The banked credits were then used each year to offset 50 per cent of reduction commitments in developing nations. The banked credits are sufficient to offset the first decade’s worth of reduction commitments by about 50-80 per cent for Annex III and IV nations, respectively.

Cumulative emissions in this scenario are 605 Gt C, a “penalty” of only about 15 Gt C relative to a similar scenario without early cooperative partnerships (ME 450). The slower start in reductions permitted after 2010 by the “banked” credits in the JI scenario is compensated for by the slower exponential growth in the period 2000-2010 that occurs because of the decreased deployment of fossil fuel-based energy infrastructure assumed to result from JI. This penalty is insignificant when one realizes that investments in efficiency and renewable energy technologies are required in developing countries today if early transitions to efficient, low-carbon economies are to occur at all. Banked credits also provide developing nations with flexibility in crafting appropriate strategies for meeting eventual emissions-reduction obligations. Moreover, many analysts have observed that there is significant potential for inexpensive or cost-saving carbon-reduction projects using current or near-term technologies, suggesting that our proposed early interventions are not only possible but both environmentally and economically beneficial.

Finally, banking will also promote the earlier development of an appropriate international funding environment. Internationally funded development projects in the energy sector have concentrated on deploying, rather than avoiding, fossil fuel-based energy. Consider, for instance, the record of the World Bank. The World Bank is formally committed to carbon reduction, and funds JI projects through the Global Environment Facility. In the past decade, however, roughly 20 JI projects have been implemented, with a total cost of under US$1.6 billion and a carbon impact of about 0.14 Gt C over two decades. On the other hand, in the 1990s the World Bank directly sponsored energy projects totalling at minimum US$12 billion, accounting for at least two orders of magnitude higher levels of emissions than the carbon savings represented by the JI projects. The international regime should be at least carbon neutral in project support.


Our analyses suggest that beginning greenhouse gas emissions reductions immediately in developing as well as developed nations is the most effective means to confine atmospheric concentrations of carbon dioxide to acceptable levels. Reductions today — particularly where credits can be “banked” to partially offset initial reductions commitments in the future — can be accompanied by slower rates of carbon dioxide reductions than would be required if action is delayed.

We call for such an emissions banking scheme to be part of the discussions at the COP4 meeting in Buenos Aires. This “slower start” brings greater promise that fossil-fuel energy infrastructure can be retired at the end of its natural lifetime, rather than prematurely, as may be required under delayed but faster transition regimes, and this natural retirement brings with it significant economic savings. The slower start also places less pressure on the social, political, economic and technological resources that must be brought to bear in addressing the problem of atmospheric carbon dioxide burdens.

While some have speculated that technological progress should make delaying carbon dioxide reductions less painful, innovation relies on political and economic signals. An early, moderate, JI-based start will not only promote “on the ground” experience for relevant technologies and cooperative programmes, but provide the needed political and economic signals to spur further development. Additional mechanisms for promoting investments in energy research and development and demonstration and commercialization such as carbon taxes should also be a focus of discussions at COP4.

The added advantage of focusing on JI as a means to accelerate efforts to control global climate change is that it will result in substantial investments in developed-developing nation partnerships and technology transfer. Fundamental to plans for a low-carbon society and emissions equity is the investment in infrastructure development for poorer nations. The JI projects would have to verifiably achieve long-term carbon savings and economic growth. Both the developed and developing nation partners benefit from investments in research, and in identifying, developing, and maintaining cost-effective improvements in the energy infrastructure and services provided from JI projects.

While some JI projects are, of course, already occurring, the magnitude of projects is far smaller than what we propose here, and these projects have generally been devoted to reforestation projects rather than energy projects. In the future, JI must foster change in the energy sector if we are to have any hope of containing future carbon dioxide emissions to reasonable levels. But promoting energy sector projects will require that developed and developing nations alike benefit from such interventions with respect to their own emissions mitigation obligations.

Immediate deployment of JI should satisfy reasonable demands that the developing nations be included in a mitigation process from the beginning while insuring that Annex I nations fund the initial process of mitigation. Moreover, the constraint that Annex I nations can only partially offset their emissions reduction commitments with JI guarantees that substantial restructuring of the economies of developed nations to be far less carbon intensive will occur.

The compelling evidence that developed nations do need to be included quite soon in the process — both because many current national emissions are close to or exceed those that can reasonably be expected as a long-term cap and because avoiding deployment of new carbon dioxide-intensive energy infrastructure is crucial if we are to meet long-term concentration and emissions goals — should provide sufficient encouragement to guarantee cooperative participation by all nations.

Further information

Daniel M Kammen, Energy and Resources Group, University of California, Berkeley, CA 94720-3050, USA. Fax: 1-510-6421085. Email: dkammen@socrates.berkeley.edu. Web: http://socrates.berkeley.edu/~erg/facultybio/.

Ann P Kinzig, Department of Biology, Arizona State University, PO Box 871501, Tempe, AZ 85287-1501, USA. Fax: 1-602-9652519. Email: kinzig@asu.edu.

Related publication

A longer account of this study has been published as “National trajectories of carbon emissions: Analysis of proposals to foster the transition to low-carbon economies” in Global Environmental Change, 8(3), 183-208, 1998.

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