There are so many different companies trying to influence the shape of climate policy in Washington that it's hard to get a sense for the sheer scale involved. According to the Center for Public Integrity's latest tally, there are now 1,160 businesses and groups wrangling over the issue—and they've hired a whopping 2,780 climate lobbyists. An even better sign of the frenzy is the fact that companies you'd never expect to care about the arcane details of cap-and-trade are now taking a keen interest. Like Campbell Soup and Kellogg:

"It wasn't until we analyzed what was going on in the House that we thought, 'Oh, gosh, we are being affected by this,'" said Kelly Johnston, Campbell Soup's vice president for public affairs, in an interview.

At issue are the free "allowances," or carbon dioxide pollution permits that the House-passed climate bill would give to manufacturers that use a lot of energy to produce internationally traded products, like steel and aluminum. Those energy-intensive industries fighting international competitors successfully lobbied for protection from loss of jobs to China and other cheap-energy countries if the United States unilaterally enacted a carbon reduction program that would make coal-burning more expensive here.

But the House bill's approach means manufacturers that don't use as much energy—like Campbell—would have to bid at auction for carbon emissions allowances from the federal government. Johnston argues that Campbell should either be exempt from that process or provided some freebies, too.

This looks like a fairly important development. Last summer, remember, when Henry Waxman and Ed Markey were cobbling together a climate bill in the House, they struck an intricate balance on how to divvy up the pollution permits under the cap. Some were given away gratis to big polluters or industries at risk of fleeing to China (steel, cement, aluminum, etc.); others were doled out to local electric utilities with the provision that the money would be used to cushion the blow for ratepayers; still other permits were set aside to reduce deforestation or fund new energy sources.

You can read Robert Stavins's detailed breakdown of where all the permits went—he argues that about 20 percent of the permits were pure corporate giveaways, while the rest went to ostensibly public purposes. But the point is that this was all a delicate compromise, and still the bill only barely passed through the House. Now that the bill's wending its way through the Senate, a bunch of new companies have decided to get into the lobbying game and try to force a revision to that formula. Natural-gas producers, for example, feel they got short-shifted by the House. And they have a point. But any new revision also risks alienating the industries that backed the original House bill.

Meanwhile, not all of the companies lobbying over climate change want to soften the bill or push for loopholes. As the Center for Public Integrity also reports, a number of venture capitalists and clean-tech investors are trying to push for a more ambitious carbon cap—they want the price of coal to rise as soon as possible, so that alternatives like solar become competitive earlier and provide a quicker return on their investments. (The House bill, by contrast, does a fair bit to shield the coal industry by giving coal utilities free permits for at least the first 15 years.)

(Flickr photo credit: Rose*Bud)

Follow Bradford Plumer on Twitter: @bradplumer