Smoking causes cancer. Carbon pollution causes extreme weather.

It really doesn’t have to be more complicated than that.

We dump billions of tons of carbon pollution into the atmosphere each year. As a result, the concentration of carbon dioxide has increased by 40 percent. Excess carbon dioxide traps excess heat in the atmosphere. Excess heat causes extreme heat waves, droughts, and storms.

And that’s what we have been seeing. In June alone, 170 all-time high temperature records were broken or tied in the United States, and more than 24,000 daily high temperature records have been broken so far this year. If the climate weren’t changing, we would expect to see about the same number of record highs and record lows set each year due to random fluctuations. That’s what we were seeing 50 years ago, but during the last decade there were twice as many record highs as record lows. So far this year the ratio has been 10 to 1.