Today's guest blogger, Tony Kreindler, is a Media Director at Environmental Defense.

There's been a lot of buzz lately about the Energy Bill under debate in the Senate. With all the lobbying and spin, it can be hard to sort out what's really going on. Here's the bottom line.

When it comes to solving climate change, our best yardstick for measuring success is how much we cut global warming pollution. The Energy Bill could make some progress, but it's no substitute for the comprehensive climate legislation Congress will work on later this year. Let's look at the numbers.

Most scientists say that to avoid the worst consequences of a warming world, we must cut U.S. greenhouse gas emissions 60 to 80 percent below current levels by 2050. To put us on that path, emissions from cars should drop by about 30 percent from current levels by 2025, assuming that all economic sectors do their share in proportion to their carbon footprint.

The Senate bill would only slow the growth of auto sector emissions, leaving them about 3 percent above current levels in 2025. That doesn't mean it's a bad energy bill; it just means that it doesn't solve the climate problem.

Senate Majority Leader Harry Reid said last week that the Democrats' energy plan is only the first step toward bolder action in climate change. If it's a prelude to a bill that puts a mandatory cap on greenhouse gas emissions, it's a step in the right direction.