Global carbon emissions reached a record high in 2018

Global emissions of carbon dioxide have reached the highest levels on record, scientists projected Wednesday, in the latest evidence of the chasm between international goals for combating climate change and what countries are actually doing.

Between 2014 and 2016, emissions remained largely flat, leading to hopes that the world was beginning to turn a corner. Those hopes have been dashed. In 2017, global emissions grew 1.6 percent. The rise in 2018 is projected to be 2.7 percent.

The expected increase, which would bring fossil fuel and industrial emissions to a record high of 37.1 billion tons of carbon dioxide per year, is being driven by nearly 5 percent emissions growth in China and more than 6 percent in India, researchers estimated, along with growth in many other nations throughout the world. Emissions by the United States grew 2.5 percent, while emissions by the European Union declined by just under 1 percent.

As nations are gathered for climate talks in Poland, the message of Wednesday’s report was unambiguous: When it comes to promises to begin cutting the greenhouse gas emissions that fuel climate change, the world remains well off target.

‘‘We are in trouble. We are in deep trouble with climate change,’’ United Nations Secretary General António Guterres said this week at the opening of the 24th annual UN climate conference, where countries will wrestle with the ambitious goals they need to meet to sharply reduce carbon emissions in coming years.

‘‘It is hard to overstate the urgency of our situation,’’ he added. ‘‘Even as we witness devastating climate impacts causing havoc across the world, we are still not doing enough, nor moving fast enough, to prevent irreversible and catastrophic climate disruption.’’

Guterres was not commenting specifically on Wednesday’s findings, which were released in a trio of scientific papers by researchers with the Global Carbon Project. But his words came amid a litany of grim news in the fall in which scientists have warned that the effects of climate change are no longer distant and hypothetical, and that the impacts of global warming will only intensify in the absence of aggressive international action.

In October, a top UN-backed scientific panel found that nations have barely a decade to take ‘‘unprecedented’’ actions and cut their emissions in half by 2030 to prevent the worst consequences of climate change. The panel’s report found ‘‘no documented historic precedent’’ for the rapid changes to the infrastructure of society that would be needed to hold warming to just 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels.

The day after Thanksgiving, the Trump administration released a nearly 1,700-page report cowritten by hundreds of scientists finding that climate change is already causing increasing damage to the United States. That was soon followed by another report detailing the growing gap between the commitments made at earlier UN conferences and what is needed to steer the planet off its calamitous path.

Coupled with Wednesday’s findings, that drumbeat of daunting news has cast a considerable pall over the international climate talks in Poland, which began this week and are scheduled to run through Dec. 14.

Negotiators there face the difficult task of coming to terms with the gap between the promises they made in Paris in 2015 and what’s needed to control dangerous levels of warming — a first step, it is hoped, toward more aggressive climate action beginning in 2020. Leaders at the conference also are trying to put in place a process for how countries measure and report their greenhouse gas emissions to the rest of the world in the years ahead.

But while most of the world remains firmly committed to the notion of tackling climate change, many countries are not on pace to meet their relatively modest Paris pledges. The Trump administration has continued to roll back environmental regulations and insist that it will exit the Paris agreement in 2020. Brazil, which has struggled to rein in deforestation, in the fall elected a leader in Jair Bolsonaro who has pledged to roll back protections for the Amazon.

The biggest emissions story in 2018, though, appears to be China, the world’s single-largest emitting country, which grew its output of planet-warming gases by nearly half a billion tons, researchers estimate. The United States is the globe’s second-largest emitter.

China’s sudden, significant increase in carbon emissions could be linked to a wider slowdown in the economy, environmental analysts said.

‘‘Under pressure of the current economic downturn, some local governments might have loosened supervision on air pollution and carbon emissions,’’ said Yang Fuqiang, an energy adviser to the Natural Resources Defense Council, a US environmental organization.

China’s top planning agency said Wednesday that three areas — Liaoning in the northeast Rust Belt and the big coal-producing regions of Ningxia and Xinjiang in the northwest — had failed to meet their targets to curb energy consumption growth and improve efficiency last year.

But Yang said that these areas were not representative of the whole country, and that China was generally on the right track. ‘‘There is still a long way ahead in terms of pollution control and emissions reduction, but we expect to see more ambitions in central government’s plans and actions,’’ he said.

Such changes — in all large-emitting nations — have to happen fast.

Scientists have said that annual carbon dioxide emissions need to plunge almost by half by the year 2030 if the world wants to hit the most stringent — and safest — climate change target. That would be either keeping the Earth’s warming below 1.5 degrees Celsius — when it is already at 1 degrees — or only briefly ‘‘overshooting’’ that temperature.