In 2015 in Paris, the countries of the world agreed to hold the rise in global average temperatures to “well below 2°C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels.”
How’s that going?
The unavoidably grim answer: not well, and not just because President Donald Trump has promised to pull the United States out of the accord.
Every year, the United Nations Environment Program (UNEP) releases an “Emissions Gap” report, on the remaining disparity between the world’s stated ambitions on climate and the actions it is currently taking. The 2017 edition of the report is out a week before the next round of international climate talks in Bonn, Germany. And it reports that the gap remains … substantial.
Researchers calculate that for a reasonable chance of hitting our goal, global greenhouse gas emissions must peak by 2020 and the gap must be closed by 2030 — in other words, if we are not on the right trajectory by 2030, all hope of 1.5 degrees is lost and 2 degrees is almost certainly out of reach as well.
Let’s run through a few of the top-line conclusions of the report, which was assembled by an international team of scientists based on the most recent published science.
Global greenhouse gases are still rising
There’s been a bit of (premature) celebrating over the past few years as global energy- and industry-related carbon emissions plateaued, mainly due to the remarkable slowdown in Chinese coal consumption and reductions in carbon intensity across the world.
But this good news comes with three key caveats. First, it’s a relatively mild and short-lived trend that could easily be reversed by new economic growth. Second, massive, ongoing investment in fossil-fuel technologies and reserves implies emissions far in excess of our global carbon budget. “The assessment shows that between 80 and 90 percent of coal reserves worldwide will need to remain in the ground, if climate targets are to be reached,” UNEP writes, along with “approximately 35 percent for oil reserves and 50 percent for gas reserves.”
Third, overall greenhouse gas emissions continue to rise, thanks mainly to the growing contribution of land use, land-use change and forestry, or LULUCF, emissions.
Here’s a chart. On the right are global emissions from fossil-fuel use and cement production. As you can see, they have plateaued over the last three years. On the right, LULUCF emissions are included, showing a continued (if slowing) rise.
“Emissions still show a slowdown in growth in the past two years,” UNEP writes, “with calculated increases of 0.9 percent, 0.2 percent and 0.5 percent in 2014, 2015 and 2016 respectively.”
A separate United Nations report out this week from the World Meteorological Organization finds that globally averaged concentrations of carbon dioxide reached their highest level in 800,000 years in 2016 in an unprecedented surge to 403.3 parts per million, up from 400 in 2015. The agency attributed the increase to both the strong El Niño event last year and human activities.
While G20 countries are collectively on track to come in around the middle of their 2020 pledges, many of them (including the US, Canada, and Mexico) require further action to achieve even that.
And even assuming those 2020 targets are met, we’re going to come into 2020 at the very high end of scenarios that show any hope of hitting 2 or 1.5. Obviously that’s going to make the task going out to 2030 that much harder.
Short-term action to meet and exceed 2020 targets would make the rest of the century a lot easier. As we’ll see below, global emissions need to start declining by then.
What the world promised in Paris is nowhere close to enough
Here’s the bad news: Collectively, the carbon reductions pledged by the world’s countries in Paris are woefully inadequate. Even assuming all countries fulfill their pledges, it would account for only about a third of the needed emission reductions to get to 2 degrees.
If Paris’s current pledges are a total success, it still leaves the world on track for temperature rise of more than 3 degrees. That would be ugly.
The chart below illustrates the gap. “NDCs” are Nationally Determined Contributions, each country’s pledge to reduce emissions. “Conditional NDCs,” as the name indicates, are targets that will be met conditional on some other development (new legislation, funding, etc.).
That’s … a big gap.
Note that 1.5 or 2 degree scenarios both require emissions to begin a sharp downward trajectory in 2020. Every year that downward turn is delayed, the slope downward grows steeper and further from reach.
This chart shows exactly how big the gap is:
(A GtCO2e is a gigaton of carbon dioxide equivalent — other greenhouse gases are effectively translated into CO2.)
So we’re somewhere between 11 and 19 GtCO2e off-target. Hitting current NDCs will leave the carbon budget for 2 degrees 80 percent depleted by 2030 (requiring a cliff-like plunge thereafter). The carbon budget for 1.5 degrees will be gone by then.
It’s entirely within our power to turn the situation around
UNEP writes that “the gap can be closed before 2030 by adopting already known and cost-effective technologies, often by simply adopting or adapting best practice examples already deployed in the most innovative country contexts.”
The report contains a systemic, bottom-up review, walking through six sectors — agriculture, forestry, buildings, energy, industry, and transport — and showing the mitigation potential of each. This kind of bottom-up approach typically finds greater mitigation potential than the typical top-down integrated assessment models (IAMs) usually used to calculate these things.
UNEP finds that the 2030 emissions gap could be closed entirely with measures that cost the equivalent to $100 or less per ton of CO2, often substantially less. Together, cost-effective measures in those six sectors could reduce emissions by up to 36 GtCO2e a year by 2030, easily closing the gap.
So, you know, a global $100 carbon tax could save the world. Cool cool cool.
As a side note, it is interesting to compare this six-sector focus to Paul Hawken’s Drawdown project, which takes a similar bottom-up approach but ranks a broader set of solutions. Among other things, the UNEP report misses the extraordinary potential for female empowerment — family planning and education of girls — in the developing world to slow population growth and thus reduce emissions.
A few other topics of special interest
The UNEP report is capacious. It takes a close look at a few areas that are of particular interest to current climate policy debates, if you want to dig deeper.
Chapter 4 examines the potential of “non-state action,” i.e., action by cities, states, provinces, and non-state actors like corporations. Though it makes a great deal of these actions, it finds overall that their potential is “of the order of a few GtCO2e in 2030, over and above current NDCs.” It acknowledges, however, that it’s difficult to know how these non-state pledges overlap with NDCs and good data is currently difficult to come by. It encourages non-state participants to formalize their reporting in subsequent climate negotiations.
SLCP, or “short-lived climate pollutants,” include a variety of gases that have short-term warming effects often in excess of CO2, but don’t stay in the atmosphere as long. These include methane, HFCs, black carbon (soot), tropospheric ozone, and others. Reducing emissions of these gases — for instance, by signing the Kigali Amendment to the Montreal Protocol — can have an immediate cooling effect and avoid around 0.6 degrees of warming by mid-century. Here’s a fun video from the enviably competent Norwegian government.
Hitting any serious climate target requires phasing out the global coal fleet (duh). Chapter 5 looks into how policy can accelerate (or slow) that process. “Without additional policy interventions,” UNEP warns, “the number of coal-fired power plants will continue to increase.”
The report spends some time assessing a range of carbon-removal technologies. People usually think of engineered technologies — carbon capture and storage, “direct carbon removal” — but the report stresses that biological carbon removal has enormous potential. Better management of forests, wetlands, and soils could save between 4 and 12 GtCO2e a year, though there is considerable uncertainty and some studies project much higher numbers. Land-based carbon removal solutions not only remove carbon, they also “present opportunities to meet other global sustainability goals, such as improved water quality, ecosystem restoration, biodiversity preservation and improved crop yields.”
To get there, we gotta start now
NDCs will be revised for the first time in 2020. It is critical, UNEP says, that ambition be substantially ratcheted up. “Missing the 2020 option of revising the NDCs,” it starkly warns, “would make closing the 2030 emissions gap practically impossible.”
Between now and 2020, there is a “facilitative dialogue” around the Paris agreement in 2018, to take stock of progress toward the larger goal. (Subsequently, every five years, there will be a more formal “global stocktake” of progress.) Before that meeting, the IPCC will release a special report on climate change impacts, starting at 1.5 degrees and going up. That report is expected to inform the dialogue.
It is at that dialogue, UNEP says, that countries must agree to go bigger. There’s no more time for delay.
And of course, they will have to do so with the US playing either no role or an actively dilatory one. The key will be for other countries to stay focused, to avoid getting pulled into the attention-draining media sinkhole that attends everything Trump does.
On climate change, as on other pressing global issues, the US is actively withdrawing from global leadership. We’ll find out next year whether the world can keep moving forward without us.