Over my last three months in Washington, I’ve seen that history often comes down to a handful of votes.

On March 18, while the rest of Congress bickered over health care, a Democrat, a Republican and an Independent released the outline of a national climate and energy bill. If the Senate votes on this bill, it will, like health care, come down to a handful of votes, and it will help define the history of this century. And for the next month, the Kerry-Graham-Lieberman bill needs your support.

Why do we need a national climate and energy bill in the first place? Despite “ClimateGate” and erroneous Intergovernmental Panel on Climate Change reports about Himalayan glaciers, man-made global warming pollution threatens to alter the global climate, erase biodiversity and disrupt civilization in unpredictable and potentially catastrophic ways. In February, NASA released global temperature data showing that 1999-2009 was the warmest decade on record. Atmospheric concentrations of heat-trapping carbon dioxide are the highest they’ve been in 400,000 years, and they are on track to double again by 2100. Poor equatorial countries like Chad and Bangladesh are projected to suffer the bulk of the resulting economic damage, even though America has contributed more to the atmospheric stock of carbon dioxide than any other nation.

Free markets and technological innovation can solve many problems. But without government intervention they won’t solve the climate crisis. The math just doesn’t work. According the Energy Information Agency, U.S. carbon intensity — the amount of carbon dioxide pollution needed to produce a dollar of GDP — declined by an average 2.7 percent per year between 2004 and 2008. That’s the result of solar, wind, smart grid, clean coal, carbon sequestration, fuel efficient vehicles … everything. To avoid dangerous levels of climate change, the U.S. has to cut its total emissions by 80 percent by 2050, which requires carbon intensity to decline at more than twice this current annual rate. In other words, the market needs to hurry up, but, to paraphrase author and 350.org founder Bill McKibben, it can’t while it continues to allow ExxonMobil to use the atmosphere as a free open sewer for the carbon dioxide that is an inevitable byproduct of the product it sells.

That’s why we need a national climate and energy bill — to put a price on pollution and to give the market incentives to cut emissions and develop low-carbon energy sources.

The Kerry-Graham-Lieberman Senate bill would get the job done. First, it sets an economy-wide cap on global warming pollution: 17 percent below 2005 levels by 2020 and 80 percent by 2050. It would allocate these reductions using a market-based trading system: The federal government would sell a fixed number of pollution emission permits to utilities and manufacturers, who could trade the permits as needed; the government would rebate half of the resulting revenue to taxpayers. To protect these firms from excessive risk and loss, the bill would be phased in gradually and prices would not be allowed to fluctuate beyond a certain range. Only firms that emit more than 25,000 tons of carbon a year would face regulation. Finally, the bill would include the usual package of politically-motivated carrots and sticks: fees on petroleum refining, subsidies for clean energy, nuclear power and off-shore drilling.

Admittedly, the bill isn’t perfect, but it would attain big reductions in global warming pollution at little cost the economy, and crucially, it actually has a chance of passing in the Senate.

Through conversations I’ve had on Capitol Hill and in Washington think tanks, I’ve learned the bill has a one-month window within which it could feasibly come to a vote. Starting now. After April 23, Senate policy committees begin closing for summer recess; not long after, Senators begin campaigning hard for reelection, effectively pushing off new legislation until 2011.

If the Democrats lose seats in the Senate, climate legislation is dead until at least 2012. Climate change will continue unabated.

This is where you come in. We have one month to persuade Senators to support the Kerry-Graham-Lieberman bill and slow climate change. So write a letter to your senators — Senate staffers actually read your letters. Call them — they actually mark down the side for which you are calling! You won’t be alone: The Yale Student Environmental Coalition, along with organizations at other universities and people nationwide will be lobbying senators this month.

Climate change isn’t someone else’s problem — it’s our problem, Yale’s problem. Issues like health care and immigration reform have built-in political constituencies. Climate change doesn’t because it threatens voiceless groups like the poor, future generations and non-human life, and it requires a sophisticated understanding of science, economics and politics combined with access to political power in places like Washington.

The bottom line is that we Yalies: young, educated, affluent, soon to be in positions of power, are better situated than any other group to take leadership in the political battle to slow climate change. Let’s start now by lobbying our senators to support the Kerry-Graham-Lieberman climate and energy bill.

Sam Massie is a 2009 graduate of Jonathan Edwards College and an intern at the Department of the Treasury.