The world is on track to warm by a potentially catastrophic 3.4 to 3.9 degrees Celsius by 2100, according to a dire new United Nations report analyzing current climate policies.
The UN “Emissions Gap Report 2019,” published on Tuesday, highlighted the urgent need for aggressive policies to curb emissions.
“We have to learn from our procrastination. Any further delay brings the need for larger, more expensive and unlikely cuts,” Inger Andersen, executive director of the United Nations Environment Program, wrote in the report’s foreword. “We cannot afford to fail.”
The amount of greenhouse gas emissions is continuing to build up in the atmosphere year after year, hitting a record high of 55.3 billion metric tons of climate pollution (measured in “carbon dioxide equivalent”) in 2018. The only way to prevent the most catastrophic climate impacts is to quickly reverse this trend, a challenge that only gets harder the longer countries wait to take action.
The Paris climate agreement, signed by hundreds of countries in 2015, aimed to limit future warming to 1.5 to 2 degrees Celsius below pre-industrial levels. Since then, the stakes have only risen. Scientists have learned the climate is changing faster than previously thought, and that even a slight increase in global temperatures could result in massive coral reef die-offs. An increase in extreme weather events is already hurting the economy.
The annual UN report, which measures how far off-track the world is from meeting its climate goals, concluded that global greenhouse gas emissions must drop 7.5% each year over the next decade to limit warming to 1.5 degrees Celsius, or 2.7% each year to limit warming to 2 degrees Celsius.
If the world had taken stronger climate action in 2010, by contrast, countries would have only had to cut emissions 0.7% a year to meet the 2-degree target and 3.3% to hit the 1.5-degree goal.
The Group of 20 (G20) countries account for most — about 78% — of the world’s emissions. While in 2009 the group pledged that it would phase out fossil fuel subsidies, no country has so far committed to doing so by a specific year.
And several of these countries are not on track to meet their individual climate pledges to date, including the United States and Canada. President Donald Trump vowed in 2017 to withdraw the US from the Paris agreement, and his administration has aggressively rolled back many climate rules and initiatives in recent years.
Meanwhile, only five G20 participants, including the European Union, have committed to eventually achieving net-zero emissions, meaning that they would release the same amount of emissions as they can pull out of the atmosphere through natural or man-made processes.
Even if every country across the globe was on track to meet their stated climate targets, the world would still be headed to warming of more than 3 degrees Celsius by 2100, the report found.
The new report also outlined steps for how specific G20 countries can boost their climate action going forward. The United States could implement carbon pricing to achieve a carbon-free electricity supply and to reduce industrial emissions, as well as implement new clean building and vehicle standards. Japan, India, and China could all aim to be coal-free. The European Union could stop investing in new fossil fuel infrastructure, including natural gas pipelines.
“This report gives us a stark choice: set in motion the radical transformations we need now, or face the consequences of a planet radically altered by climate change,” UN’s Andersen wrote.
World leaders will gather in Madrid next week at COP25, the UN's convention on climate change, to hammer out the final details of implementing the Paris climate agreement and discuss how countries can do more to address the crisis.
Emissions reached a record high of 55.3 billion metric tons of climate pollution in 2018. The amount was misstated in an earlier version of this post.