Ken Ward takes a worthwhile look at the goalposts for U.S. climate policy in his argument for making 350 parts per million the new bright line for success. We agree that we need to aim lower than 450 ppm — the world is at roughly 380 ppm now, and we’re already witnessing adverse climate impacts.

But we part ways when it comes to how we’re going to get there. Ward suggests that EDF’s support for the Lieberman-Warner Climate Security Act can’t be reconciled with a stabilization target below 450 ppm, because the bill as written wouldn’t drive sufficient emissions reductions. In fact, there’s nothing incompatible about the two. Here’s why:

First, the climate effects that we are seeing at today’s concentration levels are only going to get worse as emissions rise unabated. We shouldn’t agree to a weak proposal, but delaying action until we get a bill that achieves all the necessary reductions in one fell swoop may simply condemn us to more pollution and increasingly dangerous climate change. In addition, getting back to today’s concentration levels (or below) will mean managing unchecked emissions growth not only in the U.S., but in the large emitting countries that are waiting for us to act before stepping forward. We need to act — before its too late.

Second, aggressive short-term pollution reduction targets like those in the Climate Security Act are an indispensible part of the equation for deeper long-term reductions. A strong 2020 target tells companies to start cutting pollution now and investing in low-carbon technologies. When the early reductions are achieved at lower-than expected costs — and the technology to produce cleaner energy is scaled up — legislators will have the assurances they need to set even stronger goals.

Grist thanks its sponsors. Become one.

Congress will undoubtedly revisit the targets and timetables for U.S. climate policy over the next four decades, and any bill should require that based on science. What we need now is strong action — to begin making the pollution cuts we urgently need to stabilize greenhouse gas concentrations at or below today’s levels, and to give Congress the confidence that tighter long-term limits are both achievable and cost-effective. Delay only means steeper cuts, higher costs, and lower chances to achieve either of those goals.