Evidence Of Warming Overwhelming

LITTLE ROCK — Since about 1990, we’ve seen the opinions of global warming skeptics evolve from “there is no global warming” to “anyway, it’s not caused by humans” to “anyway, it won’t be that bad.”

Now word is coming in that it will indeed be “that bad.”

Years ago, scientists established a global average temperature rise of 2 degrees Celsius (3.6 Fahrenheit) as a boundary which, if exceeded, would probably have “dangerous” implications. So far, we’ve seen a rise of 0.8 degrees Celsius.

Last year, the British scientifi c journal Philosophical Transactions of the Royal Society published an article by Kevin Anderson and Alice Bows titled “Beyond ‘Dangerous’ Climate Change: Emission Scenarios For a New World.” The paper looks at the amountof carbon dioxide (CO2) now in the atmosphere and plausible CO2 emissions scenarios for the future, concluding “there is now little to no chance of maintaining the global mean surface temperature at or below 2 degrees Celsius.

Moreover, the impacts associated with 2 degrees have been revised upwards, suffciently so that 2 degrees now more appropriately represents the threshold between ‘dangerous’ and ‘extremely dangerous’ climate change.”

I’ve read the paper (just search on the title) and, like all good science, it’s based solidly on conservative,rational thought and real evidence from the natural world. Importantly, it’s peerreviewed, which means climatologists familiar with this research area read it carefully and critically prior to publication, and vouched for its scientifi c accuracy.

Another important part of the scientifi c process is the critique of new research by the broad scientifi c community. I can tell you if I publish dubious research, colleagues will delight in rebutting it. Global warming skeptics believe there’s a grand global warming conspiracy, just in order to get research grants. Reality is quite the opposite. Any scientist who fi nds solid evidence against global warming has his or her fortune made, as part of the normal scientifi c process.

The actual problem for skeptics is not that there’s a conspiracy; it’s that all the evidence points toward the reality of global warming.

The scientific process makes it diffcult to avoid reality.

There’s insuff cient space here to present much of the massive evidence that global warming is real and caused by humans.

I recommend climate scientist Michael Mann’s “The Hockey Stick and the Climate Wars” as a good book that tells it like it is.

Here’s a sample of that evidence: The concentration of CO2 in the atmosphere is now 390 parts per million (ppm). During the past 2-million-year ice-age period, this concentration has varied up and down between 180 ppm and about 280 ppm, oscillating in sync with the temperature.

So the atmospheric CO2 concentration is now 40 percent higher than it’s been in two million years. Since CO2 is a major “greenhouse gas” that traps heat, normal people, including scientists, would expect this to increase Earth’s temperature, which it has.

Further evidence: It can be absolutely verifi ed thisincrease in CO2 is caused by fossil fuel burning since about 1800. Atmospheric CO2 is slightly radioactive because cosmic rays from space hit atmospheric nitrogen, converting it to the radioactive form of carbon called C-14. Thus all biology is radioactive with a little C-14.

But C-14 “decays” in about 5,000 years, so older carbon such as fossil carbon is not radioactive. So it’s possible to distinguish between nonradioactive fossil carbon and radioactive atmospheric carbon. When scientists study tree rings older than 200 years, they fi nd no fossil carbon (as judged by the radioactivity of the tree rings), but more recent tree rings show more and more fossil carbon. The unavoidable conclusion is the rise in atmospheric CO2 comes from fossil carbon, i.e., from fossil fuels that are many millions of years old.

Ninety-seven percent of climatologists who publish on climate changeagree global warming is happening and is caused by humans. A 2004 survey of a year’s worth of peerreviewed research articles on this topic, 928 papers in all, concluded that “remarkably, none of the papers disagreed with the consensus position” (search on “the scientifi c consensus on climate change”).

Those who cherrypick the evidence or who otherwise thoughtlessly dismiss the science behind global warming are fl ying in the face of nature. Their intellectual dishonesty has pushed the world beyond a dangerous tipping point. It’s hard to think of anything more immoral.

We are already reaping the consequences in extreme weather, melting ice, rising oceans and drought-caused forest fires, but it is our grandchildren who will bear the real burden.

ART HOBSON IS A PROFESSOR EMERITUS OF PHYSICS AT THE UNIVERSITY OF ARKANSAS.