Rich Dunn guest column: Climate change must be addressed now

In his recent guest commentary, climate change skeptic Fred LaSor stated: “The glacier-cut mountains around Lake Tahoe are testimony to a much colder period before humans walked the Earth, and records of grapes growing in far northern latitudes show just the opposite. To say man is responsible for these fluctuations is egotistical.”

Of course, nobody is saying man is responsible for the glacier-cut mountains around Lake Tahoe. That line of argument employs what’s called the straw man fallacy, and is just one example of the sophistry employed by the fossil fuel industry to sow confusion and doubt among the general public on the subject of climate science.

There’s no such confusion among climate scientists themselves, because they know how to read the data and understand the physics involved. Having said that, let’s get down to cases.

Plants take in CO2 and release oxygen due to photosynthesis during the day. At night they take in oxygen and give off CO2 due to something called respiration. That’s all part of the carbon cycle, which has been stable in the biosphere for a long time.

The empirical evidence shows plants have adapted to a stable CO2 load, which has cycled between 200 and 300 parts per million for more than 800,000 years, at least until recent times. They do this by recycling. The carbon cycle takes the same amount of CO2 out of the environment as natural processes put in.

Then in the 19th century we humans discovered a tremendous amount of carbon-based energy from decomposed plants and animals had been locked up underground for millions of years. Before long we were releasing more CO2 into the environment than the biosphere was capable of processing.

While it’s true to say the natural carbon cycle liberates more CO2 than humans do, it also recycles all of that CO2. The net gain in CO2 from natural processes is still zero. If this weren’t the case, the atmosphere would be mostly CO2, and conversely, if the carbon cycle took in more CO2 than was released, we would all quickly freeze to death. The CO2 balance in the air is all-important to the survival of life on this planet.

Since the start of the industrial revolution, we’ve added more CO2 to the environment than the carbon cycle is capable of processing. Even if we stopped doing that today, it would take thousands of years for the environment to adapt. But we haven’t stopped. On the contrary, we’re releasing more and more sequestered carbon dioxide into the biosphere all the time. Consequently, carbon dioxide levels are now above 400 parts per million and rising.

Since the beginning of the industrial revolution, carbon dioxide concentrations in the atmosphere have increased by more than 40 percent, mostly since 1960. Human activities currently release about 37 billion metric tons of CO2 per year, equivalent to about 5 percent of natural CO2 emissions. Natural processes absorb the equivalent of all natural emissions plus about 57 percent of those man-made emissions, leaving an additional 16 billion metric tons of CO2 in the atmosphere every single year.

That’s the science. Deciding you’re a climate skeptic won’t change any of it, nor is it going to stop that 40 percent increase in atmospheric carbon dioxide from causing profound and permanent changes in the global climate. The non-binding Paris Accord won’t even take effect until 2020, and between now and then India will double its coal production. That reflects the lack of any genuine sense of urgency among world leaders, who will pass the consequences of their inaction onto future generations.

Rich Dunn is Secretary of the Carson City Democratic Central Committee, and was the 2012 Democratic candidate for Assembly District 40.