A mounting sense of urgency will greet negotiators as they arrive at this year’s United Nations Climate Change Conference in Poland. In 2015, after 20 years of trying and failing to reach a global accord on climate-changing emissions, 195 nations hammered out a deal, the Paris Agreement, that all of them could accept.
Three years on, it’s becoming increasingly clear that national decisions about climate action, which country negotiators will convey in Poland and over the next two years, will determine whether the breakthrough Paris pact succeeds both on a political and emissions reduction front.
As scholars at the MIT Joint Program on the Science and Policy of Global Change, we have closely followed the global climate change agreements and studied their implications. Based on our analysis of nations’ commitments to cut emissions, getting the world on track to achieve the agreement’s signature goal – to keep global warming below two degrees Celsius – will require far more ambitious climate action than what countries have pledged so far. This action must begin sooner rather than later to avoid the worst consequences of climate change, from severe droughts to extreme flooding.
Climate change won’t wait for humanity’s response
Climate change is the type of problem where delay is especially costly. It is not like other pollution such as dirty urban air or a putrid stream. For these, people might clean up a polluted area this year, but if they put off the task, there will probably still be the same opportunity to get it done the following year.
Not so with greenhouse gases, which hang around for decades to centuries. So if societies delay revising our current practices – burning fossil fuels, chopping down forests, planting more polluting crops like rice, as well as raising cows – the total amount in the atmosphere will grow. The goals for limiting global warming will get steadily more difficult to achieve.
In addition, as the nations’ representatives gather in Poland to pursue their effort to gain control of this process, a crucial decision point is rapidly approaching.
In the Paris Agreement, each nation is to make a pledge (what the agreement calls a Nationally Determined Contribution) to achieve a level of emissions control by a target date. For most countries this is the year 2030. They will also submit to a review of whether they did what they said they would do every two years.
Our analysis shows that, fortunately, meeting these Paris pledges will halt emissions growth at least to 2030, though without additional action growth will resume thereafter. This voluntary system of pledge and review represents real progress on this difficult issue. Experts in international affairs argue that it is perhaps the best deal possible for a 195-nation agreement.
The pledges for 2030 are just the first step, however. Getting the globe onto a path to the 2°C Paris goal, much less to meet its stretch objective of 1.5°C, will require stronger action beyond 2030.
How tough the emissions restrictions must be in the next decade or two depends on the pace of reduction that may be feasible later in the century – and here emerging technology could possibly play a role. For example, a significant effort is underway to develop techniques to suck carbon dioxide (CO2) out of the air and store it underground. If we could count on this option becoming available and affordable in the future, participating nations in the Paris Agreement could relax their emissions controls a bit now and the temperature goal could potentially still be met.