In his fight against global warming, President Obama has issued new regulations on power plants' emissions of carbon dioxide and other greenhouse gasses.

Republicans blast the rules as “job destroyers” and a “war on coal.” Democrats attack Republicans as shills for Big Coal and “science deniers.”

Both sides need to grow up, and the climate debate needs to be shifted to reasonable grounds. In short, Republicans need to stop denying that climate change is real, and liberals need to admit that they don't have all the answers.

There are things we know with a good level of certainty, and conservatives should grant these:

In general, the Earth’s atmosphere is getting warmer. Of course, there is no single temperature of the atmosphere. Even speaking of an “average” is a bit tricky, because our temperature stations are irregularly spaced, and of varied reliability and longevity. But the aggregate of the data shows a general upward trend in temperatures on Earth.

We know that carbon dioxide, methane and some other gases will (all else being equal) increase atmospheric temperatures by trapping heat. This is the infamous greenhouse effect.

We also know that human industrial activity - such as burning coal and oil - adds to the concentration of greenhouse gasses.

Predicting the future is much harder, despite the certainty with which alarmists promise 20-foot sea-level rises, the death of bees and rising beer prices due to climate change.

Climate has always changed. Climate will change. Climate is massive, insanely complex and inherently unpredictable.

We do know that greenhouse gas concentrations are rising pretty rapidly, indicating that the warming trend will continue. Not all change is bad, but in general, rapid change in complex systems is disruptive and bad. While plants and animals can adapt—and have always adapted—they’re better off adapting slowly to gradual change. While human society can adapt, it will cost money and lives.

Conservatives need to come to grips with these facts. Too many Republican politicians simply declare, “climate change is a hoax.” This is a bad habit partisans and ideologues on both sides display: If the other side proposes an undesirable policy response to a problem, just deny the existence of the problem.

Democrats have aggressively tried to brand Republicans as “anti-science,” on all sorts of issues, particularly climate change. While some truth is in that charge, the Left takes it way too far.

You can now get pegged as a “climate denier” for any deviation from the most alarmist script. In this regard, the Left shows a strong anti-science streak by refusing to acknowledge uncertainties and weaknesses.

Scientists’ climate models are intricate and complex, but they’re also ultimately guesswork. Future “feedback effects” can be both positive and negative: On one hand, warmer oceans release more CO2, causing more warming; on the other hand, warmer air means more plants, which suck up CO2 to grow.

Most effects of climate change may be negative, but many will be positive: more farmable land, for instance.

But beyond papering over uncertainty, the Left grossly overstates how effective their favored policies will be in changing the temperature.

President Obama famously promised to slow the rise of the oceans. If the climate models are correct, though, we would have to get on a path for abolishing all burning of coal, natural gas and oil in order for the oceans to slow their rise in Obama's lifetime.

Obama's Environmental Protection Agency trumpeted spectacular benefits of their new proposed rule, but the agency based its predictions on the assumption that the rest of the world would clamp down on power-plant emissions to the same extent as the U.S.

Environmental regulations and subsidies often fail to live up to their promises. Democrats like Obama have long promoted ethanol as a clean fuel, but as the EPA considers dialing down the ethanol mandate, the Environmental Working Group recently found that the federal ethanol mandate increases greenhouse gas emissions.*

Similarly shutting down U.S. coal-fired power plants will exacerbate emissions in some parts of the world. Less U.S. consumption of coal has pushed U.S. coal producers to focus more on foreign markets. African, Asian, and South American coal-fired plants generally have inferior pollution-control systems. And with coal looking cheaper, expect power companies to build more of these plants.

There's plenty of uncertainty in the climate debate. The debate would be better, if conservatives admitted what we do know — and liberals came to grips with what they don't know.

*CORRECTION: Originally this article stated that the EPA found that the ethanol mandate adds to CO2 emissions. It was EWG that found this.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at His column appears Sunday and Wednesday on