Another way to think about the question of whether climate change is caused by humans is to simply look at how we’ve changed the landscape. (First understand that carbon dioxide or CO2 causes warming, regardless of the source, regardless of nature’s variability.) Forget all of the numbers. Forget all of the data. Just look around. Next time you’re in an airplane, look at how we’ve changed the landscape. Look at the square miles of homes, businesses, stores, apartments — all of the buildings. Look at the miles and miles of roads and highways. Next time you’re stuck in traffic on a congested interstate, look around. Contemplate all of the similar, major metropolitan areas around the United States and the whole world. Rush hour is not one hour long; it lasts multiple hours, morning and evening both. We’ve all seen the pictures of choked highways in Los Angeles. Look at those exhaust pipes.

Now, just think about all of the natural gas, the gasoline, the diesel and the coal flowing and burning to keep these things running and illuminated. Think about how the land was 100 years ago. There were far fewer square miles covered with buildings. There were far fewer cars and trucks.

Forget the numbers — just contemplate how we’ve changed the landscape. Ask yourself if all of these changes, all of these sources of CO2, could grow without having some effect?

Then, ask yourself: “So what?”

CO2 causes warming, that’s a scientific fact. But let’s just say for a minute that all of man’s practices have not changed our climate. So what if we make more CO2?

If past changes are just “natural variability,” can we afford to put more pressure on the system by generating more CO2 on top of any natural variability?

Even if some believe that humans have not caused the changes in the climate so far — will that serve as a guarantee into the future? What will happen if we keep putting more and more CO2 into the atmosphere? Can anyone assure us it is OK to pump out all we want?

The good news is that the changes occur somewhat slowly. The bad news is that the changes occur somewhat slowly. If the changes were very rapid and prolific, we’d be in deep trouble, right now. We would know it, and we would take great steps to reverse climate change. (But it might be too late.) Luckily, the changes are not extremely rapid or prolific. We have to recognize the changes that are occurring. Look around. Look for the changes. Do you see changes?

We also have to understand that some changes are occurring that may go unnoticed to many, such as the oceans turning more acidic from the CO2 (another scientific, indisputable fact of chemistry). What is going to happen when the oceans cannot absorb it as quickly or cannot absorb any more CO2 at all? There will be all the more CO2 staying in the atmosphere.

When you have your cold drink this summer, with ice in it, you’ll know that it stays cold. When the ice is gone, the temperature of the drink rises quickly. The ice is our insurance buffer, absorbing heat. When the Earth’s ice is gone, and the oceans cannot take more CO2, it may be too late.

There is no “down side” to saving energy (saving money), or getting more of our “fuels” from renewable sources. There is no meter on sunlight. Let’s start now.


Peter Berglund, of St. Paul, is an environmental engineer.