LIMA - Recent pledges by China, the United States and the European Union to limit greenhouse gas emissions will slow the rate of global warming this century, a study by climate scientists showed on Monday.

But the study, released during UN talks on a climate deal in Lima, said temperatures were still on track to breach a promise by almost 200 nations to limit global warming to 2 degrees Celsius (3.6 Fahrenheit) to avert more heat waves, floods and rising sea levels.

The Climate Action Tracker indicated that average temperatures would rise by between 2.9 and 3.1 degrees Celsius because of the promised actions by the three top emitters, about 0.2 to 0.4 degrees Celsius less than previously projected.

It was the first time in five years that promised actions had reduced projected warming under the tracker, compiled by European research groups Climate Analytics, the Potsdam Institute for Climate Impact Research, Ecofys and the New Climate Institute.

China has promised its emissions will peak around 2030, while the United States aims to cut greenhouse gas emissions by 26-28 percent below 2005 levels by 2025 and the EU plans to lower them to 40 percent below 1990 levels by 2030.