Michael Sanchez, in a Voices commentary last Sunday, expressed his views on climate change. A number of Mr. Sanchez’s statements are demonstrably false. Global temperatures have not been “essentially flat since 1997.” Temperature data from NASA’s website shows a steady increase in global temperature since 1978. Mr. Sanchez is confusing a seven-year stretch from the late 1990s into the mid-2000s when the year-to-year increase in global temperatures was flat, but when compared to the average temperature for the entire 20th century, each year since 1978 has been warmer than the 20th century average. And, with the exception of 1998, 19 of the warmest years have occurred since 1980, with 2016 being the warmest.
While it’s true that a cyclical global warming period started at the end of the last ice age, about 12,000 years ago, this increasing trend is better understood by comparing it to temperatures and CO2 levels recorded over the last 800,000 years. This data comes from ice core samples taken from the Greenland Ice Sheet. These temperature data show eight cooling periods followed by eight warming periods. And in between these cooling and warming trends are numerous and consistent fluctuations.
Of upmost significance are the corresponding CO2 levels, which increase and decrease in close correlation with the changes in temperature. Science informs us that these cycles have been triggered by cyclical changes in the Earth’s axis tilt and orbit.
As the Earth warms, CO2 is released from the ocean to the atmosphere because gases are less soluble in water as temperatures rise. As a greenhouse gas, CO2 (as well as water vapor, methane and a few other minor gases) has the unique characteristic of absorbing infrared light from the surface of the earth and lower atmosphere. Not all gases have this special quality, including nitrogen and oxygen, which together make up 98 percent of the Earth’s atmosphere. Greenhouse gases do have this special quality, therefore they are pivotal in controlling global warming.
This is an important point. Just 2 percent of the gases in the atmosphere have the ability to regulate global temperatures. Think of them as the regulators of global temperatures.
So, during the last 800,000 years, Earth’s temperature has gone up and down in correlation with changes in CO2. Most importantly, the ice core data reveals that at no time during the last 800,000 years have CO2 levels exceeded 300 ppm when Earth was at its warmest. These natural cycles, caused by changes in the Earth’s axis tilt and orbit, are always there and would be expected to once again trigger changes that would lead us to the next ice age.
But this time humankind has added something new to the equation. For the first time, greenhouse gases are being added to the atmosphere from a new source ? the burning of coal, oil and natural gas (methane). What this does is further increase the atmosphere’s ability to trap heat.
By the way, the science behind the greenhouse effect was worked out over 150 years ago and is not in dispute. It’s been tested and retested and refined all along the way.
Where are the CO2 levels now? In 2015, for the first time in the last 800,000 years, CO2 levels exceeded 400 ppm. Whereas changes in CO2 levels that brought them to 300 ppm in the past, occurred over thousands of years, mankind has increased CO2 levels from 300 ppm to over 400 ppm in just 100 years. This rapid increase in CO2 levels is unprecedented.
Science informs us that we can expect temperatures to continue going up (they are lagging behind the rapid increase in CO2 because the Earth’s ocean is acting as a huge sink, slowly absorbing this added heat) even if we were to stop burning fossil fuels today. The die has been cast, so to speak.
The only proven way to stop this dangerous warming trend is to lower the concentration of greenhouse gases in the atmosphere and allow more heat to escape into space.
More than any other country on the planet, the U.S. has benefited from the burning of fossil fuels. Our contribution to the rise in CO2 levels since the Industrial Age is staggering and mandates, on moral grounds, that we lead the rest of the world to an economy whose energy comes from non-carbon sources. Besides the moral argument, we should see this as an economic opportunity to transform the world’s economy in ways that don’t endanger the very life processes our survival as a species depend upon.
I share John Kelley’s frustration that climate change is not being taken more seriously. We are engaging in a dangerous experiment that is bringing us closer to an outcome that we are not going to be able to control nor recover from.