Environment-watchers have elsewhere noted that planet Earth is about to hit a dubious milestone: Sometime very soon, the levels of carbon dioxide, a greenhouse gas, will reach 400 parts per million. That's the highest ever recorded according to the Scripps Institution of Oceanography, which is providing daily updates of the atmospheric measurements that have been taken every day at the Mauna Loa Observatory in Hawaii since 1958. (Click here to see the graph in a larger format.)

The Sunlight Foundation took a look at what the Mauna Loa graph looks like compared to some of the political datapoints we like to follow. What it suggests is that we citizens of the world like to talk the talk about improving the environment but have a hard time moving from words to action.

The concentrations of CO2, implicated in global warming, have continued to climb inexorably despite increased attention on the environment, beginning with the first Earth Day in 1970. The upward trajectory didn't slow when NASA scientist James Hansen told Congress in 1988 that global warming had begun, or when voters replaced President George H.W. Bush, a Texan with close ties to the oil industry, by Bill Clinton, a Democrat whose vice president, Al Gore, had just published Earth in Balance, his alarm about the state of the planet's environmental health.

It continued through three major international summits on the climate and a 2007 Nobel Prize to Gore, which he won after producing a movie about climate change, An Inconvenient Truth.

One reason for the less-than-satisfactory outcomes of the international summits: It's hard to reach international consensus when the United States, the world's top consumer of oil, can't reach consensus at home.

To provide some perspective on why that might be, Sunlight has overlaid data we keep onto the Mauna Loa graphic. Fossil fuels, which produce carbon dioxide and other gases implicated in global warming, are a big part of the influence industry in Washington. Our records, which start in 1989, show that campaign donations by the oil and gas industry reached a peak in 2010 -- the same year as the collapse of the last major effort to reach a bipartisan deal on reducing emissions of carbon dioxide and other gases implicated in global warming.

Lobbying expenditures by the American Petroleum Institute also spiked during that congressional session to $14.2 million, almost twice what the trade association spent during the previous two-year cycle, according to data on Sunlight's Influence Explorer. That doesn't include what the industry has been spending on a sophisticated public relations campaign. According to its most recent publicly available tax filings, the American Petroleum Institute spent more than $82 million on public relations in 2011.

Also worth noting: The prominent role that energy consumption plays in the U.S. economy. Of the top ten entries in the newly-released Fortune 500 list of the nation's biggest revenue-producers, four are energy companies and two are automakers. No. 1 on the list is Wal-Mart, a major shipper.

One other data point of note: As carbon dioxide levels have continued to go up, mention of the greenhouse gas has gone down in Congress. Follow this link to a chart, taken from Sunlight's Capitol Words, that suggests that the climate has been drawing less attention from the nation's lawmakers of late:

(Contributing: Caitlin Weber, Alison Rowland, Kathy Kiely)