(Excerpt) According to climate scientists, averting the worst consequences of climate change requires that the increase in global temperature should be limited to 2°C (or 3.6°F). to achieve that objective, global emissions of green house gases (GHGs)—the main human cause of global warming—must be reduced to 50 percent of 1990 levels by 2050.

The key to successful climate change abatement at those scales lies in leveraging the collective actions of developed and developing countries. Cumulatively, developed countries have been responsible for most human emissions of GHGs. that picture will be quite different in the future as emissions from the developing world take over the top mantle. Given this dynamic, there is a general agreement internationally that developed countries will lead emissions reductions efforts and that developing countries will follow with “nationally ap- propriate mitigation actions.” turning that agreement into environmentally beneficial action requires close international coordination between the developed and developing countries in allocating the responsibility for the necessary reductions and following up with credible actions. However, the instruments employed so far to promote the necessary collective action have proved to be insufficient, unscalable, and questionable in terms of environmental benefit and economic efficiency.

Currently, the most important and visible link be- tween developed and developing countries’ efforts on climate change is the Clean development Mechanism (CdM). the CdM uses market mechanisms—the “carbon markets”—to direct funding from developed countries to those projects in developing countries that lead to reductions in emissions of warming gases. In reality, the experience with the CdM has been mixed at best since its inception in 2006. while the CdM has successfully channeled funding to many worthy projects that reduce emissions of warming gasses, it has also spawned myriad projects with little environmental benefits. overall, the CdM has led to a significant overpayment by developed countries for largely dubious emissions reductions in developing countries.

Interest in nuclear disarmament has grown rapidly in recent years. Starting with the 2007 Wall Street Journal article by four former U.S. statesmen-George Shultz, Henry Kissinger, William Perry, and Sam Nunn-and followed by endorsements from similar sets of former leaders from the United Kingdom, Germany, Poland, Australia, and Italy, the support for global nuclear disarmament has spread. The Japanese and Australian governments announced the creation of the International Commission on Nuclear Non-Proliferation and Disarmament in June 2008. Both Senators John McCain and Barack Obama explicitly supported the vision of a world free of nuclear weapons during the 2008 election campaign. In April 2009, at the London Summit, President Barack Obama and President Dmitri Medvedev called for pragmatic U.S. and Russian steps toward nuclear disarmament, and President Obama then dramatically reaffirmed "clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons" in his speech in Prague.

There is a simple explanation for these statements supporting nuclear disarmament: all states that have joined the Nuclear Non-Proliferation Treaty (NPT) are committed "to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament." In the United States, moreover, under Clause 2 of Article 6 of the Constitution, a treaty commitment is "the supreme Law of the Land." To af1/2rm the U.S. commitment to seek a world without nuclear weapons is therefore simply promising that the U.S. government will follow U.S. law.

A closer reading of these various declarations, however, reveals both the complexity of motives and the multiplicity of fears behind the current surge in support of nuclear disarmament. Some declarations emphasize concerns that the current behavior of nuclear-weapons states (NWS) signals to non-nuclear-weapons states (NNWS) that they, too, will need nuclear weapons in the future to meet their national security requirements. Other disarmament advocates stress the growth of global terrorism and the need to reduce the number of weapons and the amount of fissile material that could be stolen or sold to terrorist groups. Some argue that the risk of nuclear weapons accidents or launching nuclear missiles on false warning cannot be entirely eliminated, despite sustained efforts to do so, and thus believe that nuclear deterrence will inevitably fail over time, especially if large arsenals are maintained and new nuclear states, with weak command-and- control systems, emerge.

Perhaps the most widespread motivation for disarmament is the belief that future progress by the NWS to disarm will strongly influence the future willingness of the NNWS to stay within the NPT. If this is true, then the choice we face for the future is not between the current nuclear order of eight or nine NWS and a nuclear-weapons- free world. Rather, the choice we face is between moving toward a nuclear- weapons-free world or, to borrow Henry Rowen's phrase, "moving toward life in a nuclear armed crowd."

There are, of course, many critics of the nuclear disarmament vision. Some critics focus on the problems of how to prevent nuclear weapons "breakout" scenarios in a future world in which many more countries are "latent" NWS because of the spread of uranium enrichment and plutonium reprocessing capabilities to meet the global demand for fuel for nuclear power reactors. Others have expressed fears that deep nuclear arms reductions will inadvertently lead to nuclear proliferation by encouraging U.S. allies currently living under "the U.S. nuclear umbrella" of extended deterrence to pursue their own nuclear weapons for national security reasons. Other critics worry about the "instability of small numbers" problem, fearing that conventional wars would break out in a nuclear disarmed world, and that this risks a rapid nuclear rearmament race by former NWS that would lead to nuclear first use and victory by the more prepared government.

Some critics of disarmament falsely complain about nonexistent proposals for U.S. unilateral disarmament. Frank Gaffney, for example, asserts that there has been "a 17 year-long unilateral U.S. nuclear freeze" and claims that President Obama "stands to transform the ‘world's only superpower' into a nuclear impotent." More serious critics focus on those problems-the growth and potential breakout of latent NWS, the future of extended deterrence, the enforcement of disarmament, and the potential instability of small numbers-that concern mutual nuclear disarmament. These legitimate concerns must be addressed in a credible manner if significant progress is to be made toward the goal of a nuclear-weapons-free world.

To address these problems adequately, the current nuclear disarmament effort must be transformed from a debate among leaders in the NWS to a coordinated global effort of shared responsibilities between NWS and NNWS. This essay outlines a new conceptual framework that is needed to encourage NWS and NNWS to share responsibilities for designing a future nuclear-fuel-cycle regime, rethinking extended deterrence, and addressing nuclear breakout dangers while simultaneously contributing to the eventual elimination of nuclear weapons.