Is It Even Possible to Get the Entire World to Carbon Zero by 2050?

Ask a Scientist - August 2010

B. Bailey from Ottawa, Ontario, Canada, asks "If the political will were there, is it even possible to build enough wind, solar, hydro, geothermal, advanced vehicles, etc, to get the entire world to carbon zero by 2050?" and is answered by Steve Clemmer, Director of Energy Research

To avoid the worst effects of climate change, scientists say we must cut world-wide global warming emissions by at least 50 percent. The United States is currently the second largest contributor to these emissions—so we have a lot of cutting we need to do. Thankfully, the Union of Concerned Scientists found that we can cut U.S. heat-trapping emissions by at least 80 percent from 2005 levels by 2050 and many of the technologies needed to make this happen already exist today.

So how do we do it?

Overall, to reduce heat-trapping emissions we must do three main things:

reduce the amount of energy we waste,
get the energy we do need from cleaner sources, and
store more heat-trapping carbon in our forests and soil instead of the air.

Let’s start with the first one.

To reduce the amount of energy we waste, we must consider all the major sources of heat-trapping emissions—these include electricity, industry, buildings, and transportation.

The energy used to power, heat, and cool our homes, businesses, and industries and the fuel we use for transportation are responsible for more than 80 percent of global warming emissions in the United States. Much of that energy ends up wasted, so, improving energy efficiency is the quickest, most cost-effective strategy for cutting carbon emissions.

Innovative technologies and common-sense measures are available now, and can transform how our industries, buildings, and transportation system use energy over the next two decades

For example, in our homes and commercial buildings, we can use better insulation, install highly efficient windows, and switch to ultra-high-efficiency boilers, furnaces, and air conditioners that are already available today. Industries can integrate new technologies into industrial processes including using more efficient motors, advanced sensors, wireless networks, and computerized controls to optimize energy use.

In our cars, we can use off-the-shelf technologies like turbocharged direct-injection gasoline engines, high-efficiency automatic-manual transmissions, engines that shut off instead of wasting fuel while idling, improved aerodynamics, and better tires (among many others) to make our vehicles go farther on a gallon of gas. Many of these technologies can also cut fuel use from our delivery trucks, buses, and big-rigs. More advanced vehicles, such as hybrids, can push fuel efficiency even further.

Because these technologies more than pay for themselves in reduced utility and gasoline bills, they not only reduce the amount of energy we need to produce, but they also save consumers hundreds of billions of dollars each year.

Next, we must address the fact that the classic suburban American lifestyle is predicated on driving a personal car a growing number of miles. I know I know, American’s love their cars, and with good reason. Cars are fun and convenient, but by designing cities and neighborhoods in smarter ways that integrate housing, shopping, parks, jobs, and transit—we can not only reduce heat-trapping emissions, but also enjoy a whole lot of other benefits such as less time spent stuck in traffic, shorter car trips, more space for walking and biking, improved public transit, and more healthy, vibrant, and desirable communities.

After we squeeze the energy waste out of our system, we then need to have clean, low-carbon energy sources to power the needs of our growing population and strong economy.

The major renewable energy technologies (wind, solar, geothermal, bioenergy, and hydropower) together have the technical potential to generate more than 16 times the amount of electricity the nation now needs. Solar and bioenergy can also provide direct heat for buildings and hot water.

Several renewable energy technologies are available for widespread deployment today. Others are projected to become commercially ready in the next two decades. Wind power has the greatest near-term potential. A comprehensive study by the U.S. Department of Energy found that electricity generated by wind has the technical potential to provide more than 10 times today’s U.S. electricity needs. That study also showed that expanding wind power from providing a little more than 1 percent of U.S. electricity in 2007 to 20 percent by 2030 is technically and economically feasible, and would not affect the reliability of the nation’s power supply.

UCS analysis demonstrates how utilities can generate about 40 percent of our electricity from renewable sources by 2030—with 48 percent of that renewable power coming from wind, 23 percent from waste biomass and sustainable energy crops, 11 percent from central solar plants, and the other 18 percent from geothermal, landfill gas, solar PV, and incremental hydro combined.

Providing clean energy sources for transportation is a bigger challenge, but significant progress is possible. Cellulosic biofuels (fuels produced from grasses, wood waste, and even garbage rather than corn) can replace 20 percent of the fuel used by our more efficient cars, trucks, busses, and big-rigs by 2030. And 20 percent of new cars and trucks in 2030 could run on electricity or hydrogen, with many more after 2030.

Lastly, let’s look at options for reducing and storing heat-trapping emissions in our forests and soil instead of our air.

How we manage U.S. forests and farmlands has a major impact on our net emissions of carbon dioxide and other heat-trapping gases. The United States has almost 750 million acres of forests covering public and private lands. These forests are important storehouses of carbon, with some 245 million metric tons of carbon dioxide equivalent stored in trees, vegetation, and forest soils. A combination of natural disturbances and human activities, including timber harvests, fire, pest infestations, and deforestation can release that carbon back into the atmosphere as carbon dioxide. The United States is also home to some 1,400 million acres of farmland used for crops and grazing. Various agricultural practices, such as tillage and the use of herbicides, insecticides, and industrial fertilizers, release heat-trapping emissions into the atmosphere. Numerous studies suggest significant potential for carbon storage in U.S. agricultural soils and forests if they are properly managed.

So, just how much have we reduced emissions and saved energy through all these solutions? Let’s look at the numbers:

By implementing solutions that save energy from industry and buildings and reduce fuel use from transportation we can reduce total U.S. energy consumption by one-third compared to 2030 projections and more than 20 percent compared to 2005.
By replacing the most polluting coal plants with renewable energy technologies, and making up the rest of the mix using mostly existing hydro and nuclear plants and natural gas, we can reduce heat-trapping power plant emissions by 84 percent below 2005 levels by 2030.
By building smarter, cleaner vehicles and fuels and giving people more transportation options, we can reduce carbon emissions from transportation by 19 percent below 2005 levels by 2030.
By expanding forests, reducing deforestation, and implementing better management techniques of current forests and farmlands, it’s estimated that this land has the potential to sequester the equivalent of 13–20 percent of what the nation’s carbon emissions were in 2005.

So while no single answer exists to solve the problem of climate change, our analysis shows that by implementing a set of solutions at the international, national, state, and local levels we can make big progress in reducing heat-trapping emissions. It is technologically and economically feasible and we can save consumers and businesses hundred of billions of dollars by doing it. And while we have only studied the United States in detail, other countries have comparable options.

Of course, these changes won’t happen by themselves. We need smart energy policies like incentives and standards for improving efficiency and developing clean, low-carbon fuels and electricity sources. We need more funding for research and development of advanced technologies, especially to keep prices coming down and to continue to reduce emissions after 2030. And most importantly, we need to stop letting companies dump carbon into the atmosphere for free, through a mechanism like a declining carbon cap, to really unleash innovation and investment in low-carbon technologies.

I’ve just synthesized a 200-page UCS report for you, so trust me, if you want more details about any of the things I’ve talked about above, you can find them all here.

As director of energy research in the UCS Climate and Energy Program, Steve Clemmer conducts research on the economic and environmental benefits of implementing renewable energy technologies and policies at the state and national levels. He holds a M.S. in energy analysis and policy from the University of Wisconsin-Madison.

The Union of Concerned Scientists is the leading U.S. science-based nonprofit organization working for a healthy environment and a safer world. Founded in 1969, UCS is headquartered in Cambridge, Massachusetts, and also has offices in Berkeley, Chicago and Washington, D.C. To subscribe or visit go to: http://www.ucsusa.org