After three relatively flat years, greenhouse-gas emissions from fossil fuels and industry picked up again in 2017, rising an estimated 2 percent, according to the Global Carbon Project. The shift was driven by rising carbon pollution in China and India, which more than offset a slight decline in the United States.
The news punctured tentative hopes that the recent flattening was solidifying into a trend. Among other things, it means that our collective climate efforts haven’t even prevented greenhouse-gas levels from increasing, at a point when we need to be radically cutting them. Keeping temperatures from rising beyond a dangerous 2 °C will require slashing emissions as much as 70 percent by mid century, according to the U.N.’s Intergovernmental Panel on Climate Change.
At more than 400 parts per million, we’re already well beyond dangerous levels of carbon dioxide concentrations in the atmosphere, as climbing temperatures, melting ice caps, and extreme weather events have made clear.
In early November, the World Meteorological Organization declaredthat 2017 was likely to end up as “one of the three warmest years on record,” and the warmest one altogether that wasn’t influenced by an El Niño event. That also makes the global average temperature during 2013-2017 the hottest five-year average recorded.
Carbon dioxide can remain in the atmosphere for thousands of years and takes about a decade to reach its maximum warming effect. In other words, even with all the changes we’ve already seen, we have yet to experience the full impact of the carbon we spewed in 2008 and every year since. Each additional ton we emit going forward only increases the dangers of climate change, multiplying the economic, environmental, and human toll.