The 2015 Paris agreement on climate change, which came into force in 2016, commits nearly every nation in the world to lowering greenhouse gas emissions, a first major step toward global consensus and cooperation on combating climate change after years of United Nations-led negotiations. But environmental scientists have moved on, asking this question: What if that milestone agreement is too little or too late? Global temperatures have been hitting record highs in recent years and population is growing significantly, putting more pressure on the planet’s sustainability.

Furthermore, under the agreement, individual governments set their own targets, which they alone are responsible for meeting. Some are already putting off action for economic or other reasons. There is also clamor from skeptics or climate-change deniers, who argue against all scientific evidence that human activity is to blame and that no radical fixes are needed. The vacillating Trump administration has its share of deniers.

Indeed, Scott Pruitt, the head of the United States Environmental Protection Agency, said today that carbon dioxide was not a primary contributor to global warming, a remark contradicting global scientific consensus on climate change.

The global goal of the Paris agreement is to prevent the earth’s temperature from rising more than 2 degrees Celsius, or 3.6 degrees Fahrenheit, below the level at the beginning of the industrial age. Numerous experts say that a goal of 1.5 degrees Celsius would be better for the health of the planet, but that would be only the first step toward fending off disastrous patterns of drought, flooding and violent storms. These patterns have damaged livelihoods, taken lives and driven many thousands of desperate migrants from dead land in some of the poorest nations to find lands where they might survive.

The next step, concurrent with the reduction of greenhouse gases, would be a leap into human intervention or science-based tinkering with the planet’s atmosphere. It is known as geoengineering. An environmental scientist explained it this way:

“This term is an umbrella for a set of imagined technological responses to climate change,” said Simon Nicholson, co-director of the Forum for Climate Engineering Assessment at American University in Washington, D.C. “We are not talking here about energy transition or the building of seawalls. We are talking about a very different class of technological responses, large-scale interventions and Earth systems that might be at a scale and of a tenor that we have not seen before.

“Climate-engineering technologies are typically organized into two different categories,” he said, speaking at the Carnegie Council for Ethics in International Affairs, which launched an initiative on geoengineering in February in New York to draw together experts in the field.

“On the one hand, there are technologies to draw down greenhouse gases from the atmosphere and to then hold those gases in long-term storage or put them to beneficial use — these are called ‘carbon dioxide removal’ or ‘greenhouse gas removal’ technologies,” Nicholson said. “Or we have technologies to alter the planet’s energy balance by reflecting some amount of incoming sunlight back into space or more readily allow outgoing solar radiation to leave the atmosphere.”

Concepts like these and other large-scale interventions have encouraged and excited some environmental advocates but terrified others. If the challenge of reaching agreement on greenhouse gases took years to achieve — and only by letting each nation set its own goals — intervening in the working of the Earth itself would demand the creation of new institutions of global governance on a planetary basis with no feasible opting in or out.

The Carnegie Council’s new project reflects this in its title: the Carnegie Climate Geoengineering Governance Initiative, and the emphasis among speakers at the launch, representing a variety of institutions, backgrounds and interests, turned on the issue of how to find universal framework support for something so extraordinary as tampering with our small part of the universe to avoid future catastrophe for billions of people. Opposition would be formidable. (A video of the event is here.)

Jennifer Morgan, co-executive director of Greenpeace International and formerly the global director of the climate program at the World Resources Institute, voiced her concerns at the event but also expressed willingness to play a role in the discussions to come.

“Greenpeace is opposed to the concept of geoengineering,” she said. “We think it is a distraction that is going to change policy decisions and people’s behavior for the worse. And it could have unpredictable and uncontrollable adverse consequences, and actually could even bring more chaos and inequality without any guarantee that it would do anything positive to counteract climate change. We also think that research funds should be better spent investing on the things that are controllable.

“But we recognize that proposals for geoengineering research are there; they are coming forward,” Morgan added. “So we very much see the need for the development of a global, transparent, and effective regulatory and control mechanism for the governance of geoengineering research so that consistent, precautionary, noncommercially driven decisions can be made regarding the legitimacy, the scientific value, the necessity, the legality and the potential impacts.

“We are engaged in this and will continue to work toward the development of such governance mechanisms wherever possible, and we are pleased to be part of this discussion to do so,” Morgan said, reflecting the views of those who may have doubts but want to be part of the thinking and planning.

Janos Pasztor, who will direct the new Climate Geoengineering Governance Project for the Carnegie Council, has been a senior adviser on climate change to the UN secretary-general and was a former science director at WWF International. He spoke of the challenges ahead:

“We cannot say for sure how far the intensive mitigation that countries have to do will take us,” he said. “We are not here to judge that. We know that they have to do it, and that is the number one priority, that emissions have to be reduced, whatever we do.

“But what we know is . . . that there are a set of technologies that may potentially contribute to the solution. But the reality is . . . that we do not know enough about them even to test their viability. And what we know even less is . . . the governance frameworks that we would need.” He added that any potential regulatory or intergovernmental governance system had to be equitable among nations.

“So here the question comes around in a different way,” he said. “Can we design a system that will be good for everybody; or, if it is not good for everybody, what can we do about that? These are the kind of governance challenges that our initiative is going to try to address.”

Barbara Crossette is a trustee of the Carnegie Council for Ethics in International Affairs.

Barbara Crossette

Barbara Crossette is the senior consulting editor and writer for PassBlue and the United Nations correspondent for The Nation. She is also a member of the Council on Foreign Relations. She has also contributed to the Oxford Handbook on the United Nations.

Previously, Crossette was the UN bureau chief for The New York Times from 1994 to 2001 and previously its chief correspondent in Southeast Asia and South Asia. She is the author of “So Close to Heaven: The Vanishing Buddhist Kingdoms of the Himalayas,” “The Great Hill Stations of Asia” and a Foreign Policy Association study, “India Changes Course,” in the Foreign Policy Association’s “Great Decisions 2015.”

Crossette won the George Polk award for her coverage in India of the assassination of Rajiv Gandhi in 1991 and the 2010 Shorenstein Prize for her writing on Asia.