A report issued by the International Energy Agency (IEA) suggests that coal will surpass oil as the world’s most popular fuel source within 10 years, threatening to inject more greenhouse gases into the air than ever before if policy changes don’t follow the warning.

The boost in coal use is due to extreme growth in emerging markets like China and India, countries that require cheap fuel sources for electricity production in order to support their quickly growing infrastructures and populations. At current rates of growth, the IEA says that it expects that coal consumption will rise to 4.32 billion tonnes of oil equivalent versus 4.4 billions tonnes of oil per year worldwide within only four years; with that trend continuing, coal would quickly overtake oil as the world’s fuel source of choice.

The IEA is the energy advisory arm of the Organization for Economic Cooperation and Development (OECD), a group that oversees the economic activities of 34 industrialized nations, including Canada and the United States.

With loose policies governing greenhouse gas emissions, developing nations are more likely to turn to coal as a cheap fuel source, despite it being the worst source of pollutants among fossil fuels, the IEA says. As the United States focuses more on shale gas reserves, India is expected to become the second largest coal consumer in 2017, ranking only behind China.

For its part, ever-growing China will remain the world’s largest coal consumer, accounting for more than half of global consumption, for the foreseeable future, with the IEA predicting an increase in Chinese demand for coal of 3.7 percent per year, dropping to 2 percent per year in the case of an unexpected slowdown of the world’s most quickly expanding economy.

Ending its report with the tagline “China is coal, coal is China,” the IEA sees that country as determining the course of the global coal market over the next five years.