Carbon dioxide emissions hit a record high in 2012, but could have been even higher, according to a new report. The increase in emissions was only 1.1 percent in 2012, compared to an average 2.9 percent over the past decade. The slowdown in emissions growth suggests renewable energy, efficiency and cleaner fuels are having a beneficial effect.

A report by PBL Netherlands Environmental Assessment Agency and the European Commission’s Joint Research Centre crunched the numbers for 2012′s carbon dioxide emissions.

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The report calculated that total carbon dioxide pollution emissions reached 34.5 billion tonnes (38.03 short tons) in 2012. The United States, China and the European Union pumped out 55 percent of the global total, but the rate of annual increases in emission from those three dropped.

The top polluter, China, created 29 percent of the total, but the rate of increase dropped to 3 percent from an average 10 percent per year in the past decade. This reduction is a step along China’s plan to reach a maximum level of energy consumption by 2015 and increase the use of natural gas in place of coal by 10 percent by 2020, noted the report.

Switching to natural gas helped the United States decrease carbon dioxide pollution by four percent in 2012. The United States now accounts for 16 percent of total CO2 emissions.

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However, the decrease in the United States came at a possible cost. Much of the increase in natural gas supply came from the controversial practice of fracking, or hydrolic fracturing. Research suggests fracking can pollute groundwater, cause earthquakes and cause other problems. However, proponents of fracking point out that using natural gas in place of coal produces lower carbon dioxide emission and thereby helps slow the increase of the greenhouse effect and climate change.

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The European Union also reduced emissions. A decrease in trucking and reduced energy consumption helped the European Union reduce emissions by 1.6 percent. The European Union produced 11 percent of total carbon dioxide pollution in 2012.

Renewable energy use accelerated in the past decade. Renewables now provide 2.4 percent of humanity’s energy. That represents a doubling in output since 2006. However, it took 15 years for renewables’ output to double after 1992. This faster doubling time suggests that continuing investments in renewable may result in even less time being necessary to double again.

This story was provided by Discovery News.