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Global Climate Change

Author: Michael Oppenheimer
November 5, 2003
Council on Foreign Relations


Prepared by
Michael Oppenheimer
Woodrow Wilson School and Department of Geosciences
Princeton University

September 19, 2003


Human-induced climate change is without doubt the most troubling and complex environmental problem facing the United States, as well as most other countries individually, and the world as a whole. The unique combination of environmental, economic, and human security concerns embodied in the climate problem and its proposed solutions ought to place it among the highest long term priorities for policy makers. However, the atmospheric persistence of the greenhouse gases that cause global warming, their origins in the current fossil-fueled economy, the dependence of the problem’s ultimate solution on technological invention and innovation, and the large uncertainties in predictions of specific outcomes present unfamiliar challenges. The resolution of the climate problem will require new institutions and new international arrangements. A nascent political, scientific, economic, and diplomatic infrastructure to deal with climate change has begun to emerge. Nevertheless, longstanding institutional deficiencies in national governments and intergovernmental agencies, in addition to current US policy, create obstacles to the timely development of this infrastructure.

The Problem

Greenhouse gases, particularly carbon dioxide from fossil fuel burning, trap heat that would otherwise escape into space. Their atmospheric accumulation has increased markedly since pre-industrial times due to human activity. The natural greenhouse effect (due to natural levels of these gases) maintains an equable climate by keeping Earth about 60 degrees Fahrenheit warmer than it would otherwise be. The enhanced greenhouse effect resulting from industrial emissions and other sources will inevitably lead to a yet warmer Earth. If emissions are not constrained, Earth will likely warm well beyond temperatures experienced in the 10,000-year history of civilization, and much faster than previous sustained global climate changes of that era. Earth has warmed about 1 degree F over the past 140 years and the Northern Hemisphere is warmer than any time in the past 2,000 years at least; the buildup of greenhouse gases is very likely the major contributor to these changes.

Among the expected consequences of future warming are increased extremes of heat and heat-related deaths, fewer extremes of cold, increases in both drought and flooding frequency and intensity at different locations and times, shifting agriculture productivity with gains in some northern locations and relative declines in many developing countries, loss of habitation, agricultural land, wetlands, beaches, and infrastructure to a rising sea, and loss of ecosystems and a narrowing of biodiversity. The risk of large and abrupt climate changes (as occurred in the distant past for natural reasons) which could overwhelm adaptive capabilities, increases later in the century . Over a longer time period, global warming of several degrees could lead to loss of the major ice sheets of Greenland and West Antarctica with very large implications for sea level and climate.

Uncertainties in projection of climate changes are large at the global level and even greater at the regional level. The range of projections of the former, about 3 to 10.5 degrees F over this century and more beyond, reflects current shortcomings of computer models, particularly their assessment of potential changes in cloudiness. At the low end of projections, warming would disrupt many ecosystems and present significant challenges to developing countries and some sections of the US, particularly low lying areas affected by sea level rise. At the high end, catastrophic outcomes cannot be ruled out. There is as yet no agreed upon assessment of the relative probability of occurrence of either extreme, or of any one of the outcomes in between.

Troublesome Characteristics

Five characteristics of the physics of climate change make it a particularly nasty challenge for policy makers.

  1. The gases persist in the atmosphere for periods ranging from a decade to more than a millennium after emission. As a result, policies, which take decades to implement fully in any case, can only gradually slow the greenhouse gas accumulation. A related consequence of persistence is that relatively large emissions decreases, on the order of half or more, would be required to halt the growth of greenhouse gases in the atmosphere.

  2. There is a lag between emission and consequence: The full effect of the gases is not felt for several decades or longer after their emission due to the thermal inertia of oceans and ice sheets. Analogy has been made to the relative coolness of coastal areas on warm spring days. Putting these two characteristics together, we note that limiting climate change is NOT like dialing a thermostat. It’s more like steering a supertanker, with much anticipatory decision-making needed.

  3. Warming is expected to be continuous until emissions are markedly reduced. There is no known limit to warming until the sources of the gases, like oil and coal supplies, begin to shrink. In the meantime, absent policy, atmospheric carbon dioxide amounts, now 30% above pre-industrial levels, could more than quadruple compared to pre-industrial levels.

  4. Rates of warming are expected to exceed those of any earlier, natural global-scale

    climate changes during the past 10,000 years. Such rates of change may challenge adaptive capabilities.

  5. Uncertainty in projection of changes is very large. Unpredicted, surprise outcomes are almost inevitable.

Beyond the physics of the problem, analogous difficulties arise. Emissions growth may be slowed with existing technology but multi-decadal time scales will be needed for development and implementation of new technologies to substantially reduce emissions (or capture gases post-combustion). Multi-decadal time scales will also be needed to fully develop and implement innovative policies needed to bring these changes about. Taken together, these characteristics argue strongly for defining long term objectives for climate stabilization (as discussed below) rather than implementing policy piecemeal.

Institutional and Legal Responses

UN agencies and affiliated organizations have developed a coherent set of mutually re-enforcing institutions to deal with the climate problem. Every 5-6 years, the Intergovernmental Panel on Climate Change (operating under WMO and UNEP auspices) provides assessments of the state of technical understanding that should inform policy. The International Negotiating Committee, operating with mandate from the General Assembly, produced the UN Framework Convention on Climate Change in 1992. The US and almost all other countries became parties to this agreement. Rules and other infrastructure were put in place to monitor and report emissions as well as on the measures to be taken to comply with the (voluntary) emissions constraints that apply to industrial-country parties. Within 3 years, when the UNFCCC obligations came to be regarded as ineffective, the parties set out to negotiate the Kyoto Protocol to the Convention, signed in 1997, which contained binding obligations on industrial countries, and means for funding voluntary participation by developing countries.

In addition to the valuable negotiation and assessment infrastructure established by the Convention, another of its features is expected to loom larger over time than its initial failure: In recognition of the troublesome characteristics noted above, Article 2 of the Convention invites development of a long term limit on the accumulation (or concentration) of greenhouse gases in order to avoid “dangerous anthropogenic interference with the climate system”.

The US has chosen not to become a party to the Kyoto Protocol, ostensibly due to the lack of developing-country obligations and what the Bush administration views as potentially significant costs of compliance. This despite the fact that the Protocol is designed around novel “flexible mechanisms” including international trading of emissions allowances, that are expected to markedly reduce costs, and which were forwarded by the US during negotiations. Nevertheless, with the expected ratification by Russia within the next few months, the Protocol would come into force.

If the Kyoto Protocol does come into force, and if it is actually implemented by the parties as envisioned, the combined institutional and legal framework above would represent a substantial achievement in a relatively short period. Nevertheless, in addition to the lack of US participation in the Protocol, the framework has significant shortcomings that need to be addressed.

Obstacles to Success

There are three major shortcomings in the climate regime at the institutional and legal level.

  • The lack of a means to enforce the existing climate agreements, or to deal with free-riders and other non-participants

  • Failure of national governments to integrate economic and environmental policy-making

  • Most significant, the complete lack of a mechanism for addressing the long term concerns, and associated issues of developing country participation that are inherent in Article 2 of the Convention.


The Kyoto Protocol deferred definition of a specific mechanism to enforce obligations by parties. Of greater difficulty now is the question of incentives to enhance participation, particularly with regard to the case of the US. One incentive is the nascent allowance-trading market. Some US companies will be in the position of reducing their emissions for reasons not related to climate policy, or as a hedge against future participation by the US. However, such reductions are not marketable internationally. Will US firms in this position form a unified bloc aimed at influencing US policy and ultimate engagement in the Protocol or successor instruments? Only time will tell.

In the meantime, suggestions of sanctions against the US for non-participation have been made in some quarters. While their potential efficacy has been questioned, the issue will be raised more frequently if the Kyoto regime is otherwise successful (i.e., involving all other developed countries). Of particular interest in this regard are cross-border energy content tax adjustments for products and services. If European aluminum or cars or aircraft cost more due to emissions or energy taxes aimed at Kyoto compliance, will the corresponding US products be allowed a sustained advantage?

There are mixed views on whether WTO rules allow such fees. Reaching resolution of such issues may become part and parcel to the need for WTO to better integrate the whole range of environmental and social concerns with its economic judgments.

If such formal incentives are disfavored, they are likely to be replaced by informal linkages in policy, e.g., the manner in which EU consternation over Kyoto may have decreased cooperation over Iraq.

National Government Structures:

National governments generally are not structured for coherent examination of the issues raised by climate change. EU economic and foreign ministries let the environmental ministries run their countries participation in negotiations, in nearly complete isolation. Perhaps this division has resulted in the EU’s relatively (compared to the US) “green” approach to the negotiations. But it is, ultimately, an unwise approach to policy on a problem with so many implications for trade, economy, and personal and perhaps national security. The situation in the US is even worse. While the State Department has the lead in negotiation, it is no secret that environmental issues rank below almost all others in the department’s sense of what is important. Climate policy ranks similarly in the current White House.

Under the Clinton Administration, the Vice President’s interest in climate change created a different but no less tangential relation of climate to other concerns, particularly at the State Department. Policy (ultimately sound policy at the international level in my view) was developed in isolation and was never fully integrated with other economic and political priorities. The complete lack of domestic political profile for this issue may have been one outcome of this bureaucratic approach.

That climate change is an issue of the utmost seriousness is perhaps not doubted by many of the same policy makers that ignore it on a daily basis. The difficulty is found in its inherent long time scales and multiple lags. Policy makers and politicians are under terrific pressure to handle more immediate concerns. Yet should governments continue to make judgments about oil supplies, national security, and climate change separately?

The solution will require renovation of relationships and attitudes within and among departments and ministries that ultimately handle these issues. But the task is difficult, transcending institutional reshuffling: the elevation of environmental issues to the Undersecretary level during the Clinton Administration did little to change the culture.

Lack of a Long Term Framework:

The most important problem is how to establish a long term goal for climate policy (on a multi-decade or century time scale as opposed to the decadal scale of Kyoto). Without one, intermediate steps are of uncertain value and may in fact wind up committing the world to unacceptable levels of warming. For example, near term emissions reductions on the approximate magnitude and timescale envisioned in the Protocol are probably necessary as an initial step to avoid ultimate atmospheric concentrations above 450ppm (the current value is about 370ppm). Significant near term action, perhaps on a smaller scale, would be required to avoid a doubling of carbon dioxide and an ultimate global warming of 3 to 8 degrees. A doubling of carbon dioxide may be sufficient to bring about disintegration of the West Antarctic ice sheet and an eventual 5-meter rise in sea level.

Lack of action in the near term, whether an explicit policy choice or by default as a consequence of US inaction, could inadvertently expose the world to such outcomes. Large uncertainties inhibit making long term choices. But making such choices, and preserving options like an ultimate target of 450ppm, would be preferable to watching them slide off the table for lack of any long term guidepost.

Second, the thorny issue of developing-country obligations is unlikely to be resolved absent a long term target. It is physically impossible to solve the climate problem without eventual emissions limitations in developing countries. Negotiating such limits involves questions of equity and assuring opportunities for sustainable economic development. Those discussions won’t get very far unless countries understand roughly how constraining the ultimate global limit will be.

Institutional arrangements for establishing such a target don’t currently exist. The IPCC considers its obligation to be that of helping establish the scientific and socioeconomic basis for such decisions, but not to grapple with policy. At the other end of the scale, the parties to the Convention or the Kyoto Protocol are too enveloped in near term decisions to grapple with this problem in the foreseeable future, although they have committed to begin negotiation of follow-on commitments to Kyoto’s years 2008-2012 obligation by 2005. More likely, informal processes in the scientific, NGO, and intergovernmental communities, supplemented by willing governments (like the Netherlands) will lay the groundwork for ultimate governmental consideration of the long term question.

In addition, it is of critical importance to seek specific institutional arrangements within governments and at the intergovernmental level that are equipped to keep an eye on the long term by integrating environmental, socioeconomic, and security perspectives.