Opinion » Commentaries

Humans are warming Earth

Verified data leave no reasonable doubt the Earth is warming and humans are to blame.

by

comment

SEA-LEVEL RISE IN MILLIMETERS, AVERAGED OVER THE OCEAN SURFACE:  The measurements come from NASA satellites TOPEX and Jason. This graph is taken from Dr. Steve Narem (sealevel.colorado.edu).
  • SEA-LEVEL RISE IN MILLIMETERS, AVERAGED OVER THE OCEAN SURFACE: The measurements come from NASA satellites TOPEX and Jason. This graph is taken from Dr. Steve Narem (sealevel.colorado.edu).
Local media recently published commentaries skeptical of global warming and climate change. The gist of these comments amounts to two assertions: 1. No credible evidence exists that the earth is warming (there have even been assertions the Earth is cooling) and 2. Human activities have had no discernable influence on the Earth’s climate.

 Both claims are false. There is clear and unambiguous scientific evidence that the Earth is out of energy balance and is warming. This has become obvious during the last few decades. Combustion of fossil fuels and deforestation are mainly responsible. The vast majority of scientists at the forefront of climate research agree on this.

 I doubt the assertions by skeptics were intended to deliberately mislead readers, but I think they were made without a serious attempt to become familiar with basic ideas of climate science and the data they have been tested against.

Two points need to be made before summarizing these ideas and evidence.

First, I am not a climate scientist. My background is in astrophysics. But the same laws of physics apply to stars and galaxies as they do to our climate, though the details are different. I’ve learned some of these details by personal interviews, e-mails, and phone calls with many leading climate researchers. I’ve studied numerous technical papers in professional journals they have referred me to.

Second, science progresses by continually testing and refining ideas against observations. It does not do so by assertions made without carefully verified, real data to back them up. When several independent observations confirm these ideas, scientists move on to the next level. When they conflict, more research is required.

 The most basic climate science idea is not hard to grasp. Anyone who balances a checkbook or
savings account can do so. If the Sun delivers more energy to the Earth than the Earth sends back to space, the Earth will store energy.

 NASA satellites have measured the Sun’s incoming energy over the last 35 years with extraordinary accuracy. Satellites have also measured the sunlight reflected back to space, as well as the heat radiated by Earth that escapes into space. Expressed in terms of power, there is a small imbalance between the sunlight impinging on the Earth and what the planet reflects and radiates back into space, amounting to about 0.08 Watts per square foot retained by the planet. That seems a tiny amount, until you realize the Earth’s surface is a lot of square feet! The measurements of reflected and radiated energy are slightly less precise than the measurement on incoming energy but nonetheless the result is clear. So, are there confirming observations? Yes. In a savings-account analogy, suppose your expense and income records were slightly uncertain. You could check at year’s end to see if your account had grown or shrunk. The Earth’s main “energy bank account” is the deep ocean. Observations show the ocean’s heat energy has dramatically increased in the last 40 years. And by about the amount expected from the measured energy imbalance: a confirming observation.

 Heating water causes it to expand, so we expect the sea level to rise. Another satellite (Jason) measures sea levels with unprecedented accuracy and shows them steadily rising, averaged over all the oceans’ surfaces (see illustration)—another confirming observation. But there is more: The sea-level rise is greater than that from the heat expansion. Why? Because glaciers and ice sheets are feeding ice to the ocean faster than snowfall is adding to them. How do we know? More confirming observations, including those from yet another satellite (GRACE).

There are many other confirming observations. Combined land and sea surface temperatures continue to show a steady upward trend.  Vegetation and wildlife patterns are changing. Does all this evidence mesh perfectly? Is everything understood? Of course not. But the overall result is clear.

What has caused this? The Sun? No, the observations show the Sun’s average output hasn’t changed over the last 35 years. Is it, as I hear all the time, “all part of a natural cycle”? No, the cycles of past ice ages took place over thousands of years. They were due to orbital changes of the Earth.

The present rapid warming is due to the observationally verified increase of greenhouse gases. This is observationally verified to be human induced. This has caused well-understood and observationally verified greenhouse warming.

Because of space limitations I cannot show all the data supporting what I have written nor respond to all other bits of misinformation. I invite those who are interested in learning more to come to a presentation about global warming at Atascadero Lake Pavilion at 7 p.m. on Feb. 10, or visit my website, centralcoastclimatescience.org, or email me at ray.climate@charter.net.

And no, the observations I have referred to are not part of a gigantic “global conspiracy” by greedy climate scientists hoping to enrich themselves with grant funds. That, to be blunt, is preposterous.

Dr. Ray Weymann is a retired astronomer with 40 years experience in teaching and research at universities and observatories. Since moving to Atascadero his interests have turned to public science education . Send comments via the editor at econnolly@newtimesslo.com.

Add a comment