WASHINGTON – The amount of heat-trapping pollution the world spewed rose again last year by 3 percent. So scientists say it’s now unlikely that global warming can be limited to a couple degrees, which is an international goal.

The overwhelming majority of the increase was from China, the world’s biggest carbon dioxide polluter. Of the planet’s top 10 polluters, the United States and Germany were the only countries that reduced their carbon dioxide emissions.

Last year, all the world’s nations combined pumped nearly 38.2 billion tons of carbon dioxide into the air from the burning of fossil fuels such as coal and oil, according to new international calculations on global emissions published Sunday in the journal Nature Climate Change. That’s about a billion tons more than the previous year.