A new report from ExxonMobil projects that natural gas will supply 135 percent more electricity worldwide in 2040 than in it did in 2010, overtaking coal as the largest global source of electricity generation.

Thanks in large part to that increased use of natural gas, the report projects global CO2 emissions will grow well below the rate of energy demand during that time, peaking in 2030 before falling five percent by 2040. Exxon expects the latter to occur despite an 85 percent increase in electrical demand and a 35 percent overall increase in energy demand during that 30-year time frame.

The largest increases in electricity generation will be in natural gas, nuclear power and renewable generation from wind and solar, which combined are expected to produce more than 70 percent of the world’s electricity by 2040.

However, wind, solar and biofuels will account for just four percent of electrical generation by 2040 because these renewable fuels are expensive and cannot produce energy on demand. That’s why Exxon believes natural gas will keep increasing because it will continue to serve as a backup fuel for renewables.

Increased electricity demand will be driven by improved living standards and electrification continues in developing countries. Notably many of those countries are expected to use coal (at least initially) to generate electricity, which is one reason Exxon believes CO2 emissions will be 20 percent higher overall in 2040, as half of that increase will come from developing nations.

Fortunately, developed countries such as the United States — the only country to see significant reductions in CO2 emissions in recent years — will help temper those significant CO2 emission spikes, as the below graphic illustrates:

From 2010 to 2040, Exxon expects emissions in the Organization of Economic Cooperation and Development (OECD) countries will decline by more than 20 percent and be 10 percent below 1980 levels by 2040 despite an increase in energy demand:

“In the developed countries, industrial energy demand is expected to grow slightly by 2025, as the United States and Canada see an increase in manufacturing and chemicals due to growth in production of unconventional oil and natural gas.”

And Exxon expects CO2 emissions to flatten after 2030 due in large part to an expected drop in China’s emissions after 2025 thanks to further diversification of its energy mix to go along with a decline in its industrial growth.

The fact that the U.S. is enjoying its lowest CO2 emissions in decades at the same time that natural gas has become the top domestic electricity generating fuel for five straight months is no coincidence. Fortunately, the world seems to be trending the same direction and will (eventually) follow the United States’ lead.