Several countries have policies in place demanding greater fuel economy or reduced carbon emissions from new cars, in the hopes of combating climate change.

While the average fuel economy of new vehicles in developed countries like the U.S. has notably improved over the past few years, but is it enough?

A new report released during the recent Paris COP21 climate-change summit says no.

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Developed countries are not making enough progress in improving fuel economy, while the rest of the world is making virtually no progress at all, according to the Global Fuel Economy Initiative (via Charged EVs).

The group feels that progress in developing countries is too slow to meet what it feels are necessary targets--including a worldwide fleet average equivalent to about 58.8 mpg by 2030.

That's already higher than what policy calls for, at least in the U.S.

Carmakers here are working to reach a Corporate Average Fuel Economy (CAFE) standard of 54.5 mpg by 2025--equivalent to about 40 mpg on the window sticker.

The report claims fuel economy in developed countries improved at an average 2.6 percent per year between 2005 and 2013.

But in other countries, the rate of improvement was much less significant--at around 0.2 percent.

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Researchers estimate the annual global improvement rate of fuel economy at around 2.0 percent over the past decade.

Yet while the rate of improvement in developed countries still adds up to a 20-percent increase in fuel economy--and lots of fuel saved--over eight years, researchers believe the lack of improvement in undeveloped countries is really the issue.

That's because greater number of new cars are now being sold in the those countries. They currently account for about 55 percent of new light-duty vehicle sales, researchers say.

Beijing smog

Beijing smog

It's possible that electric cars will achieve a greater share of sales in some countries, leading to much larger decreases in fuel consumption.

Indeed, large cuts in fuel consumption are possible with today's technology, believes Global Fuel Economy Initiative executive secretary Sheila Watson.

"The technology is not the problem--it's the policy commitment that is failing us," she said.

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