It is human to be hopeful. Yet, in 20 years of meetings to avert the consequences of global warming and climate change, the United Nation's Conference of Parties (COP) has failed to meet the challenge. Greenhouse gas emissions and the Earth's average surface temperature have continued to rise, while the effects on climate have become more evident and destructive. Next week the 21st meeting of the COP will begin in Paris, and there's renewed optimism that, this time, the COP will get it right.
Cause for optimism surfaced last November when the world's two largest greenhouse gas emitters reached a historic agreement. It called for China to restrain growth in its emissions, with a peak to be reached by 2030, and the U.S. to achieve a 26 percent to 28 percent reduction in its emissions. The significance of the agreement between the two nations - one developing, the other developed -- is measured less by its direct effect on reducing global warming and much more by providing a model for other nations to follow. And, it worked! By last week, commitments to mitigate warming had been submitted by 161 of the 196 nations in the COP, which accounted for more than 90 percent of circa-2010 emissions. But, even with such an outpouring of intentions, is optimism heading into COP21 justified? Perhaps. Should it be tempered? Probably.
An important parameter in assessing mitigation measures is the extent to which they reduce the amount by which the Earth's average surface temperature rises above its preindustrial value. If fully implemented, it's unlikely that the commitments would keep the temperature from exceeding 2°C, a threshold beyond which the increase would have serious, potentially unmanageable consequences. Although the rate of growth will decrease, global emissions will continue to increase, and best estimates indicate a temperature rise of 2.7 to 3.5°C by the end of the century. That said, these results are better than a business-as-usual outcome for which circa-2100 temperatures could be in a range from 3.6 to 4.5°C. Outcomes would be better yet if COP21 commitments were followed by additional mitigation measures. But, that's not the whole story. What are prospects that the COP21 commitments will not be fully implemented?
Each and every nation in the COP will face political and/or economic obstacles to implementation. Consider today's top three emitters, beginning with the U.S. Its ability to achieve its target depends strongly on the Clean Power Plan (CPP) imposed by the Environmental Protection Agency. The CPP prescribes a 32 percent reduction in power plant emissions by 2030. Specific targets are assigned to each state, along with flexibility in meeting the targets. However, 26 states view the CPP as overreach by the executive branch of government and have challenged its legality. There is also significant congressional resistance, as well the possibility of opposition by the next president. Simply put, a linchpin to the U.S. COP21 commitment may not survive legal and/or political challenges.
Coal is the largest source of global greenhouse gas emissions, and the CPP would further reduce its use for power production in the U.S. But coal is also a critical source of energy for rapidly growing Asian and African economies, none more so than China and India. Despite their determination to increase the use of carbon-free sources of energy, robust economic growth and the need to extricate hundreds of millions of people from poverty will compel both nations to rely heavily on coal. Because coal-fired power plants have contributed significantly to regional economic development, job creation and tax revenues in China, they will continue to receive preferential treatment. Construction of new power plants continues unabated, casting doubt on China's ability to eliminate emissions growth by 2030. And, with population growth from 1.2 billion to 1.5 billion by 2030 and a commitment to annual economic growth of 8 percent, India's emissions could increase more than three-fold by 2030.
Other measures to reduce GHG emissions and potential obstacles are too numerous to discuss, but one common to many developing nations in Asia, South America, and Africa merits attention. Deforestation is a major source of carbon emissions, and it has been occurring at an alarming, albeit declining, rate in tropical forests. Although commitments have been made to further curb deforestation, it's questionable whether they can be honored, however well intentioned. Much of it occurs illegally, with few nations having the resources to effectively police the practice, and, significant economic incentives will remain. Which brings us to another important consideration.
Developing nations place the blame for the problem of climate change squarely at the foot of developed nations. The issue has been divisive at previous COP meetings, and it's not going away. Led by China and India, developing nations insist that the developed nations provide significant financial assistance and technology transfer to support their mitigation (and adaptation) measures. The ability of developed nations to provide this support is problematic at best, and without it, many developing nations will fall short of their commitments.
What happens after the Paris meeting is more important than what happens at the meeting. If a meaningful start is to be made on curtailing greenhouse gas emissions, commitments made in the run-up to Paris must be honored and must be followed by additional (post-2030) commitments. But, for that to happen, it will take tremendous resolve within all nations and a spirit of cooperation and compromise between nations.
Frank Incropera is the H. Clifford and Evelyn A. Brosey Professor and former Matthew H. McCloskey Dean of Engineering at the University of Notre Dame. He is author of the book, Climate Change: A Wicked Problem - Complexity and Uncertainty at the Intersection of Science, Economics, Politics and Human Behavior.