Pollution in China's Forbidden City. Photo credit: Flickr/Francisco Diez.

Global carbon dioxide emissions are at record levels. In 2013, carbon emissions from burning fossil fuels are expected to rise to 36 billion metric tons, according to a report by the Global Carbon Project. That's 2.1% ahead of last year.

Overall global carbon emissions are up a staggering 61% since 1990, which is the baseline year for the Kyoto Protocol. If there is some good news, the rate of growth is down slightly from the 2.7% average over the past decade. Let's take a look at the top five biggest contributors to carbon's continued rise. The Global Carbon Project's new Carbon Atlas has 2012 figures and the rankings aren't likely to have changed in 2013.   

China
China tops the list as the world's largest carbon emitter, a place it has held for the past half-dozen years. In 2012, China contributed 27% of global carbon emissions, which was nearly double U.S. emissions. Worse yet, China grew its emissions by 5.9% year to year.

An increase in coal-fired power plants is the main culprit contributing to China's having the highest carbon emissions. In fact, "China's demand for coal will almost single-handedly propel the growth of coal as the dominant global fuel," according to a recent report by energy research firm Wood Mackenzie. American coal producers like Arch Coal (NYSE: ACI) and Peabody Energy (BTU) are increasing access to export markets in order to take advantage of Chinese coal demand. While China has vast shale natural gas resources that could one day mute its emission growth, the country is struggling to access these resources. 

United States
Not only does the United States no longer hold the distinction as the country with the highest carbon emissions, but its emissions actually dropped 3.7% in the most recent year, according to the Carbon Atlas. The combination of America's natural gas boom, as well as growth in renewables and a focus on energy efficiency has America emitting less than it has since 1994.

The switch from coal to gas has really made an impact in the U.S. According to the International Energy Agency, in 2007 net coal-fired electricity generation was 2.25 times that of net gas-fired generation. However, by 2012 that ratio had fallen to just 1.16 times. Cleaner natural gas being delivered in abundance has kept gas prices low and encouraged the switch.

A prime example of this is found at Duke Energy (DUK 0.07%). In 2005, 55% of the fuel Duke Energy used to generate power was coal while natural gas was just 5%. However, by 2015 natural gas will fuel 24% of Duke Energy's output, while coal will slip to just 38% of its output. While this switch has hurt American coal producers like Arch Coal and Peabody Energy, it has really helped to curb U.S. carbon emissions. 

India
Like China, India relies on coal to power its emerging economy. That is one big reason why it is the third-highest in carbon emissions and 4% of the global total. In 2012, India's carbon emissions rose by 7.7%. However, what is most concerning is the fact that of India's 1.2 billion people, nearly 400 million still are not connected to the power grid. This means one thing, emissions have only one way to go: Up.

Russia
The Russian Federation is the fourth-highest in carbon emissions. Unlike India, Russia's carbon emissions aren't growing. In fact, in 2012 its emissions actually fell by 0.9% over the prior year. However, as a large producer of fossil fuels such as oil and coal, the country will always be close to the top of the list. One other major issue is that Russia flares nearly a quarter of the natural gas produced in association with oil. However, a new target that limits flaring to just 5% was set in 2012 and is expected to be met by 2015. Once reached it should help Russia to curb more of its carbon emissions.

Japan
The Fukushima disaster has really changed Japan's outlook for carbon emissions. Japan was on pace to see its carbon emissions decline by 0.1% annually through 2040, however, by shutting down its nuclear capacity it has at the same time restarted its emissions growth. That said, an increase in energy efficiency efforts as well as in natural gas imports and the potential to tap methane hydrate deposits, should keep Japan from growing its emissions by all that much over the long term.

Final thoughts
The world emits tons of carbon each year. Unfortunately, emissions from emerging economies like India and China are growing fast and showing no signs of slowing down. However, there is some good news as some nations, like the U.S., Russia and Japan are working hard to emit less, with natural gas really helping to save a lot of emissions in the U.S.

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