There aren’t many positive things one can say about the global economic recession that, in the words of a recent New York Times article, “froze economic activity and slashed energy use around the world.”

One sliver of silver lining, reporter Jad Mouawad wrote, is that global carbon emissions, as a result of the slowdown, likely will “post their biggest drop in more than 40 years.” His article was based on a study the International Energy Agency is to release in November, projecting a 2.6 percent fall-off in carbon emissions this year.

He pointed out that the downturn in carbon emissions, “even if temporary,” as they are expected to be, “could allow advocates of stringent new limits on carbon dioxide to argue that continued progress is available using existing technology and switching to cleaner fuels, like natural gas.” He did not note whether the temporary decline also could strengthen critics of new control limits who might use the lower numbers to argue that regulatory controls are less necessary.

Along with recent scientific reports projecting a likely – and again temporary – cooling over the next decade (No serious scientist maintains that climate change temperatures will be linear or uninterrupted in response to long-term warming), the sometimes confusing data only adds to the challenges serious climate science communicators will face in coming years in adequately and responsibly informing the lay public on the issues and its implications.

The accompanying chart – available to media for reprinting with credit to graphic artist Ashley Zammitt and The Yale Forum on Climate Change & The Media – illustrates carbon dioxide concentrations (not emissions) in the context of changing economic times.

For original sources of the data used in the accompanying graphic, see the following:

Gross world product: International Monetary Fund

Carbon dioxide concentrations, Mauna Loa: Carbon Dioxide Research Group, Scripps Institution of Oceanography

Projected carbon dioxide concentrations: Intergovernmental Panel on Climate Change

World population: U.S. Census Bureau