numbers, not adjectives — D. J. C. MacKay

1  Introduction

Climate change is one of humanity’s grand challenges. How well are we, as a species, capable of responding to the requirements of sharing the resources of a finite planet?

The objective of these pages is to discuss how humanity may address climate change. The current approaches are not sufficiently effective, as seen by the continued accelerating growth of the concentration of atmospheric greenhouse gases, such as CO₂. Of course, the answer has to be some variant of: “use less fossil fuels”, but here I will address the question of how we can accomplish this? What are the properties of mechanisms which could actually succeed in addressing climate change?

There are a number of reasons why this is a challenging question. Let me just mention a few to help pin down the scope of what we are talking about. One challenge is that we’re all different. Different countries live in different environments and different levels of wealth; and different people within communities have different priorities and levels of power and influence. Another challenge is that intergenerational: showing restraint today, may have massive impacts on future living conditions, mainly impacting generations who are not currently in power. For these and similar reasons, solutions will have to have an equitable universality to bear promise. A key question will be, whether such principles can prevail over short term exploitation and profit.

The character of the climate change problem is one of policy. We know enough about climate systems to understand that the trajectory we’re on, will lead to massive hardship on a global scale. The main problem isn’t lack of fidelity of our scientific understanding, but the lack of experience with policy mechanisms on a global scale. We’ve never had to deal with such problems before, and every beginning is difficult.

Some media reports suggest that concerns are overstated, and climate change may not pose an existential threat to our species. That might well be true, but is hardly a cause for complacency; catastrophic environmental degradation may still allow some huma life, but would nevertheless be desirable for most of us to avoid. In these notes, we won’t attempt to evaluate in detail what the specific consequences will be of eg warming by say 1.5°C or 4.0°C, these considerations are outside the current scope and are discussed elsewhere. Instead we take the fundamental view, that the more the heating the more difficult the circumstances, and that the rising of the temperature must stop a some point. And the question remains how?

Some techno optimists think that the climate change problem may solve itself: future technologies may be cleaner and cheaper, and may ensure abundant green energy for all. And cite eg cheaper solar panels and electric cars as evidence. I don’t think this is a likely scenario for a number of reasons. FIrst, it’s difficult to build an energy network solely based on solar power: we use power all the time, but the sun doesn’t shine at night, and in some parts of the world, only a little in the winter. Some sectors such as air travel are very difficult to decarbonise. Technologies such as CCS (carbon capture and storage) are suggested, but they’re unproven and their implementation will certainly be more expensive than simply not doing it. Thus, we still need to find a ways of cooperating over the problem. Of course, you can never really disprove that some miraculous technology could turn out very impactful in the future, but you can adopt a cautionary principle, building plans based on technology that exists, and not blindly assuming that something will appear.