. As long as net emissions are above zero, global concentrations will continue to rise.
The consequences of this increasing concentration of greenhouse gases are stark. The average global temperature has already risen by 1°C, and some regions have had to confront temperature increases more than twice that amount. As more gases accumulate in our atmosphere, global temperatures will only increase.
Changing our global energy system comes with many challenges and costs. But the costs of inaction are clearly much higher.
At the rate we have been adding emissions, we’re on a path to more than triple the amount of greenhouse gases in the atmosphere by the end of the century, leading to average temperature increases of more than 4°C (or 7°F). This is the global average; in some regions, the temperature increase would be much higher. If we include commitments made by nations under the Paris Agreement, some estimates suggest that we could limit average warming to around 3°C by 2100.
The resulting negative impacts are well known, including more heat waves, extreme weather, wildfires, rising sea levels, increased acidification of oceans, and a heightened risk of abrupt and irreversible damage to our planet. To reduce the likelihood of the worst outcomes of climate change, we need to accelerate the shifts in our energy systems and look toward new solutions to manage risks.
The Ultimate Endpoint
Since the beginning of international cooperation on the climate issue, global goals for managing greenhouse gas emissions have been ambitious. Back in 1992, virtually all nations agreed in the UN Framework Convention on Climate Change to the objective of “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”
“Stabilization” here implies that humans must head in a direction where our net contribution of greenhouse gases to the atmosphere is zero, meaning we cannot add more than we take out. Defining “dangerous interference” is more complex, but the special report on 1.5°C of warming from the Intergovernmental Panel on Climate Change makes a strong case that we are fast approaching such “dangerous interference.” If, in fact, we pass that point, then we will need to begin pulling out more than we are putting in. We will need to achieve net negative emissions.
The international community has articulated numerous long-term stabilization targets, including 2°C and, in the Paris Accord, “well below” 2°C. But looking across the policy and technology landscape, it is clear that our current strategy for climate action is insufficient to achieve those targets. If the true goal is to stabilize concentrations at a level that avoids dangerous interference, then the world needs to commit itself not just to ambitious targets, but ambitious actions, as well.
More Proximate Objectives
Now, these goals can seem daunting—or even downright impossible—given political and economic realities. Obviously, no individual policymaker or nation has direct control over global temperature changes or the atmospheric concentration of greenhouse gases. There is an essential need for leaders to seek out more proximate targets, commitments, and frameworks that can help the world eventually achieve our loftier goals.
In recent years, leaders have emerged at the national and subnational level. Countries like the United Kingdom and France have substantially reduced their emissions and are looking to build on that progress by committing to net-zero emissions by 2050. The European Union recently announced a goal of net-zero emissions by 2050. In the United States, California and New York now have laws aiming for economy-wide reductions of 80 to 85 percent by 2050, and in New York’s case, net-zero emissions by 2050. Canadian leaders have also announced the goal of achieving a net-zero emissions economy by 2050.
Many of these goals depend on rapid progress in reducing emissions from the power sector. California, which would be the world’s fifth-largest economy if it were its own count