My Turn: It’s about the evidence
November 4, 2013
There are 2 arguments in Jeff Ridgel's column: "Al Gore Vs. Ben Bernanke." One is economic and I share the writer's concern that our national debt could hobble our whole economy. But blaming the problem on climate science? I offer some evidence-based information for those interested in the subject.
Ridgel accuses climatologists of violating the scientific method by chasing a pre-determined result as they bow to politics and money. He says climatologists claim that high CO2 levels cause warming, yet they refuse to acknowledge that just the opposite could be true. In reality, science has demonstrated that earth's heat balance operates both ways.
The "core sample data" support two mechanisms for natural global warming and cooling. The first concerns long-term Earth orbit changes in its gravitational tug with other planets. Earth gets thrown closer to the sun on intervals about every 70-100 thousand years. This causes warming because earth is nearer to the sun, and the warming increases decomposition, erosion, and other factors that cause CO2 levels to follow after the temperature increase. (CO2 follows temperature.)
In the other, shorter-term mechanism, temperature follows CO2—a key greenhouse gas that changes in concentration over time. During a cold period, photosynthetic plants and algae are less abundant, so they pull less CO2 out of the atmosphere. This allows CO2 levels to rise as volcanoes consistently pump out the gas.
Temperature then follows this rise because of the enhanced greenhouse effect. During very warm periods, photosynthesis takes off and removes excess CO2, pulling temperature back down, thus preventing the earth from overheating. This is called earth's climate buffering mechanism.
So why be concerned — it's all just natural cycles, right? By pulling fossil carbon out of the earth's interior, humans have added so much CO2 so quickly that we think earth's buffering mechanisms are getting overwhelmed.
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This is where the oft-misunderstood "hockey stick" graph comes in. This is not a graph of temperature; it is a graph of key greenhouse gas concentrations in the atmosphere, and it was first presented by an atmospheric scientist named Michael Mann, not by Al Gore.
In fact, changes in CO2 levels over time have been worked out by hundreds of climatologists analyzing ancient air bubbles trapped in ice cores. These data have been compared to marine sediments, soils, and other paleoclimate "proxies" that give us clues about past earth conditions.
Look at the graph below and see how intimately past temperature is linked with CO2 concentrations. Then, notice the spike at the end. Why hasn't temperature yet spiked in tandem with CO2? That is the source of current study, but most researchers agree there is a lag time between our sudden input of CO2 since the industrial revolution and the warming response that will likely follow. There is plenty of debate over how fast the warming might occur, however.
There is one irrefutable fact in all the data: For at least 650,000 years, CO2 concentration in the atmosphere has NEVER gone above 300 parts per million (ppm).
As you may have heard, CO2 passed 400 ppm this past year, and it is projected to surpass 900 ppm by the year 2100 without any changes in our emissions. This is far more than a "trivial factor," and the links to potential climate change have been clearly established.
"Business as usual" proponents always claim scientists are duping the public because of money. Climate change deniers claim "fundamental flaws in the research" but rarely tell us what the flaws are, and even more rarely do they publish their own peer reviewed research methods. (Google "Weathering Fights–Science, What's It Up To?")
No one can give an example of a particular scientist who has prospered from this scam, so they default to a non-scientist celebrity named Al Gore. I'm with the deniers in one way: I bristle at the thought of Gore banking $100,000 a stop while he spews carbon behind his first class airline seat, but that bitterness does not change the quality of the science or the strength of the conclusions.
It's sensible to question throwing money at a problem before we know enough about it, but that's quite different from trying to sabotage the actual search for knowledge.
Derek Larson is a Truckee resident who studied climate and earth systems biology at Stanford University.