Today, the International Energy Agency announced that carbon emissions have remained stable in the absence of an economic contraction for the first time in 40 years.

The IEA tracks emissions due to energy use; as such, factors like deforestation and concrete production could still have led to a small increase in emissions. Still, as far as energy is concerned, carbon dioxide emissions were the same in 2013 and 2014: 32.3 billion tonnes (each tonne is 1,000kg). This came despite the fact that the global economy expanded by a healthy 3 percent in 2014.

There were three previous instances where the IEA has seen falling emissions: the early 1980s, 1992, and 2009, all of which were associated with economic downturns.

"This is both a very welcome surprise and a significant one," said incoming IEA Executive Director Fatih Birol. The agency ascribes the change to expanded use of renewable energy in China and developed economies. China is also shifting away from coal in an attempt to get its pollution under control, while developed economies have emphasized energy efficiency as part of a general effort to decouple economic growth from carbon emissions.

The development comes at an auspicious time, as countries have committed to develop plans to reduce their carbon emissions in advance of a planned summit in Paris late this year. The drop in emissions suggests that these plans can be effective and come without an excessive economic cost.

This does not mean, however, that carbon dioxide levels in the atmosphere will stop growing. The current level of emissions is sufficient to drive increases of two to three parts-per-million. 2014 also saw the first time that atmospheric levels peaked above 400ppm, a milestone that the Earth probably hasn't seen for over a million years.