Green electricity isn't enough to curb global warming

According to new research published in the journal Nature Climate Change, the continued use of fossil fuels for a variety of industrial processes, to power vehicles and heat buildings, is likely to push CO2 emissions beyond manageable levels.

"We focused on the role of fossil fuel emissions that originate in industries like cement or steel making, fuel our transport sector from cars to freight to aviation and goes into heating our buildings," Shinichiro Fujimori, researcher from the National Institute for Environmental Studies and Kyoto University in Japan, said in a news release. "These sectors are much more difficult to decarbonize than our energy supply, as there are no such obvious options available as wind and solar electricity generation."

According to Fujimori and his colleagues, green transportation is essential to meeting CO2 emissions targets.

The Paris agreement called on nations to progressively curtail CO2 emissions in order to limit global warming to 1.5 degrees Celsius. To meet this target, scientists suggest no more than 200 gigatons of CO2 can be released between now and 2100. If current fossil fuel-use trends continue, however, 4,000 gigatons of CO2 will have been emitted by the end of the century.

Authors of the new study argue that relying on carbon capture and storage technologies is a dangerous strategy. Pulling carbon from the atmosphere is likely a necessity, scientists admit, but major industries, including the transportation industry, must also end their use of fossil fuels.

Researchers argue that climate pledges made by individual countries must be strengthened sooner rather than later in order to prevent continued investments in fossil fuel infrastructure, investments that lock in continued CO2 emissions.

"Climate mitigation might be a complex challenge, but it boils down to quite simple math in the end: If the Paris targets are to be met, future CO2 emissions have to be kept within a finite budget," said Elmar Kriegler, a scientist at the Potsdam-Institute for Climate Impact Research. "The more the budget is overrun, the more relevant will carbon dioxide removal technologies become, and those come with great uncertainties."

According to Krieglar, the precise CO2 budget may be difficult to calculate but the solution to the threat of global warming is clear.