There’s a correlation between the global economy and global greenhouse gas emissions. Evidence of the link was found in the 2009 economic crisis.

There isn’t much good that can be said about the so-called great recession – not when millions of people lost their jobs. But a new report says there was some good news, albeit fleeting.

The Worldwatch Institute says when the global economy crashed, emissions of carbon dioxide declined.

“We looked at greenhouse gas emissions over the past years, and what we found was that in 2009, as economies around the world were affected by the credit crunch, global greenhouse gas emissions started to decline following the slowing down of our global economic output. So, as our economies produce less, we also emitted less CO2. And in 2009, for the first time in nearly 20 years, emissions declined by 1.5 percent,” said Xing Fu-Bertaux, research associate at the institute’s Climate and Energy Program.

Even the U.S. – a big greenhouse gas emitter – saw a decline.

“In the U.S., since the recession affected primarily the construction sector, which is a big producer of greenhouse gas emissions because it uses lots of iron, steel and cement -- and in Europe because heavy industries produced less – it actually saved us some emissions,” she said.

Fu-Bertaux said similar declines can be found during the recession in the early 1980s. However, she said the decline recorded in 2009 did not last very long. In fact, emissions came back with renewed vigor.

“We also see that now that our economy’s starting to recover, global carbon dioxide emissions increased in 2010 by 5.8 percent, which is the biggest bump in the past two decades,” said Fu-Bertaux.

So, can there be a happy medium between a strong global economy and reduced greenhouse gas emissions? Fu-Bertaux said, yes, and gives Germany as an example.

“Germany has shown that it was actually possible. One of Europe’s most flourishing economies is seeing its emissions reduced, and not just because of the emissions reduction in East Germany, which was the result of their economic collapse. But since reunification, Germany’s emissions actually continued to decline. And this was mainly due to renewable energy – mainly solar, PV and wind – as well as energy efficiency measures,” she said.

PV stands for photovoltaic research that focuses on making renewable energy systems – such as solar power – more efficient and cheaper.

The Worldwatch Institute researcher said both developed and developing nations need long term policies and support for alternative energy sources – measures that Fu-Bertaux said would encourage private investment and innovation in renewable energy.