Here we will review the basics of climate change – where we currently stand; climate science 101; expected impacts of climate change on humans and natural systems; climate diplomacy and the Paris Agreement; and the surprising conclusions that derive from climate economics.
Having defined the problem in section I, we focus here on the customary solutions set. We clarify why transitioning away from fossil fuels will prove necessary and urgent, but also difficult and therefore slow. We will also consider the set of actions required to eliminate the one-third of our greenhouse gas emissions that derive from activities other than burning fossil fuels, including industry, agriculture, and our waste streams. We will pivot to the ways in which people, nations, and the natural world can adapt to whatever degree of climate change we prove unable to avoid. We conclude with the recognition that the entire customary toolset is unlikely to prevent unacceptable levels of climate change and climate damages from accruing late in this century. Net Zero is unlikely to arrive soon enough to save us from a substantially degraded climate. Our grandchildren will need further tools to navigate the world after net zero.
One category in this expanded toolset is carbon removal, by which we can both speed the path to net zero and then repair what may be a profoundly damaged climate after net zero. While trees and other biological capture mechanisms are likely to play an important role, their capacity is too limited and their storage reservoirs are too fragile for them to take center stage. In fact, they are to a substantial degree simply greenwashing. We will need to build a huge new industry roughly the size of the current global fossil fuel industry first to scrub carbon from smokestacks and eventually directly from ambient air. All that captured carbon will thereafter need to be pumped back down into the earth’s crust, which is ironically where we got it from. Think of it a bit like reverse oil drilling to clean up the toxic waste dump we have made of our atmosphere and oceans.
Unfortunately, the climate repair process via carbon capture and sequestration may take a century or more to complete, and the people alive during that atmospheric clean-up may suffer temperatures and related climate damages they consider unbearable. They would likely seek ways to immediately reduce temperatures in a manner that carbon capture does not. That brings us to the other side of our toolbox – solar radiation management. These technologies would seek to reflect back out to space a small fraction of the incoming sunlight and thereby immediately cool the planet. In theory, we could do that on the earth’s surface, or by making clouds more reflective, or by deploying giant mirrors in space. However, the most feasible and efficient way to increase the earth’s reflectivity would be to spray aerosol particles into the lower stratosphere. This appears to be doable and relatively inexpensive, but may prove to be a Pandora’s Box of unintended consequences. We would need to ensure we don’t opt for a cure worse than the disease.
Utilizing the climate repair and harm reduction tools on either side of Pandora’s Toolbox would present the world with unprecedented challenges in the realm of governance. Who would organize and pay for the huge carbon removal industry that would comprise a significant fraction of global GDP over the span of a century or more? How would those funding obligations be allocated among the peoples and nations of the earth? If we seek to increase the earth’s reflectivity, whose hand would be on the global thermostat and whose preferences would be expressed? How would we guard against unintended consequences and who would compensate any harmed parties? Are our ethics sufficiently evolved to fairly navigate the distributive, procedural, and intergenerational justice minefield in which such climate interventions would be situated? If we knew all the right answers, could rally the public support in the political arena to implement them? The full array of social science questions that would arise in the context of climate interventions is explored here.
We end by surveying the go-forward research agenda on both sides of our climate interventions toolbox and seek to fathom how we proceed from here.