http://arstechnica.com/science/2015/02/newsflash-the-greenhouse-effect-really-exists/
.....The new work, done by a US-based team, used instruments funded by the Department of Energy. Located in Alaska and the southern Great Plains, the instruments look straight up into the sky and measures the spectrum of infrared light it receives, revealing the presence of various molecules in the atmosphere, such as water vapor, ozone, carbon dioxide, and methane.
The spectrum it sees looks very much like the one we'd calculated it should see, with a few exceptions caused by heating of the instrument itself. But the precise details vary based on the factors noted above, like the weather and seasons. Using a decade-long time series, the authors are able to get all these other factors to effectively cancel out; what emerges shows "the unmistakable spectral fingerprint of CO2."
And not just CO2, but rising CO2. Over the deade the authors examined (2000 to 2010), the average level of the gas in the atmosphere went up by 22 parts-per-million. And the time series shows a steadily rising trend in its impact, layered on top of the seasonal changes. By the end of that period, the gas was retaining an extra 0.2 Watts for every square meter of the Earth's surface compared to the start.
Given longer periods of time, these measurements should allow us to confirm some of the basic features of the greenhouse effect. But they won't provide a complete picture of climate change, as they have to be done under clear-sky conditions; clouds play an important and somewhat uncertain role in both insulating and cooling the planet.
Still, it seems worth noting that the continued increase in greenhouse energy retention measured during this time coincides with a period where the Earth's surface temperatures did not change dramatically. All that energy must have been going somewhere.
Nature, 2014. DOI: 10.1038/nature14240 (About DOIs).