Japan plans to consider setting a fresh target to slash its greenhouse gas emissions by between 60 and 66 percent by fiscal 2035, government sources said Sunday, as the country braces for another sweltering summer amid global warming.

Japan, the world's fifth largest carbon dioxide emitter, currently aims to curb emissions by 46 percent in fiscal 2030 compared to fiscal 2013 levels. But it is likely on track to achieve around a 60 percent cut in fiscal 2035, which will serve as a basis for setting a new target, according to the sources.

"We don't think we can secure support from in and outside the country for a target below 60 percent," one of the sources said.

The source also said 66 percent is also a figure Japan "needs to be cognizant of, like it or not," given that a U.N. climate panel has called for a 60 percent reduction from the 2019 levels to achieve the goal of the Paris climate agreement, which amounts to a 66 percent cut from the fiscal 2013 levels -- the standard year for Japan.

Environmental groups are calling on Japan to lead by example by aiming for even deeper cuts, noting that the suggestion made by the Intergovernmental Panel on Climate Change is a world average and industrialized nations bear a heavier responsibility historically for emissions that have led to global warming.

According to a report released in April by the Japanese Environment Ministry, national greenhouse gas emissions for fiscal 2022, subtracting emissions absorbed by forests, reached the lowest on record at 1.09 billion tons of CO2 equivalent, a 22.9 percent decrease compared to fiscal 2013.

The figure indicated a "steady decreasing trend toward net-zero in 2050," the report said.

As the world strives to achieve the goal of limiting global temperature rises to 1.5 C above pre-industrial levels under the Paris Agreement, Japan is among the many countries that have vowed to attain net zero greenhouse gas emissions by 2050.

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