Understanding climate change: As easy as walking the dog

Yesterday, I saw one of the most engaging -- and yes, entertaining -- presentations on climate change yet. It showed how understanding the science can be as easy as walking your dog.

The speaker was Richard B. Alley, a geoscientist at Penn State, and he was the lead speaker at a climate change hearing held by state Rep. Greg Vitali (D., Delaware County) and the Pennsylvania House Democratic Policy Committee.

A lot of naysayers claim as proof that climate change isn't happening little snippets of data they cherry pick from the larger picture. They show it to Alley and say, "See? This shows temperatures are going down. What do you say to that?"

So Alley played a little game.

He picked a few years after 1957, when he was born, and charted the global mean temperature. It showed cooling.

He got married in 1980. Again, it looked like a period of cooling.

The couple moved to Penn State in 1988. Was that the temperatures dropping again? You bet.

And so it went. Each segment looked as if temperatures were dropping.

But when he put them all together, sure enough, the graph showed temperatures rising over all.

He likened the scenario to a person walking a dog up a hill. The dog is the weather, going all over the place. Sometimes it lags behind. Sometimes it surges ahead. Look at the dog's smaller path at any one point, and it might just as likely be going downhill as up.

But the person steadily moving shows the trajectory of climate change: Rising temperatures.

So remember that on some cold winter day when someone grouses, "Whatever happened to global warming?!"

Alley walked the audience through many more details of the science.  Nay-sayers contend global warming could be happening not because of human activities, but because of the sun. Or volcanoes. He showed the science that disproves both.

For all Alley's charm, his point was serious.

Later in the morning, former Department of Environmental Protection Secretary John Hanger made the mood even more somber.

He said there are, to be sure, "reasonable debates about how one responds" to climate change. "But to simply deny the science that has been developed with a huge amount of expense and care is deeply irresponsible," he said. "I believe it's a betrayal of our furutre ... and a betrayal of our country."

In the coming days, look for more blog posts from the event, including disciussions about flooding at the airport, the disappearing marshes of Delaware Bay and the water department's response to rising river levels and a salt line that moves upstream.

Meanwhile, you can see all the presentations here.