Global warming’s evidence in ice record

Norman Transcript Logo Trans

Global warming’s evidence in ice record

By Kathy D. Rand, Jim F. Chamberlain, Michael J. Soreghan and Catherine Hobbs

NORMAN — In light of our recent frigid blast from the polar vortex, it’s especially prudent to see the big climate picture that remains unambiguous: that of global warming.

According to the NASA website, “2013 tied with 2009 and 2006 for the seventh warmest year since 1880” and “the 10 warmest years in the 134-year record all have occurred since 2000.”

Even though the continental U.S. had only its 42nd warmest year on record, Australia was baking with its hottest year ever.

The global long-term evidence for climate change has been compiled again in the report available online, “Climate Change 2013: The Physical Science Basis, Summary for Policy Makers,” by the UN Intergovernmental Panel on Climate Change.

It states, “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia.” It was written by climate experts, including more than 600 lead and contributing authors and 50 review editors from more than 39 countries.

We invite all to read at least the summary, “Headline Statements from the Summary for Policymakers.”

Some of the long-term data were provided by measuring greenhouse gases in air bubbles from ancient ice cores. Based on these ice core records, the report concludes, “The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. Carbon dioxide concentrations have increased by 40 percent since pre-industrial times, primarily from fossil fuel emissions and, secondarily, from net land use change emissions.”

These increases in greenhouse gases correlate with increasing global temperatures.

Are temperatures still increasing? Yes — in fact, even more than previously reported. New research published Nov. 12, 2013, by Cowtan and Way (Quarterly Journal of the Royal Meteorological Society) has shown that over the past 16 years, global surface temperatures have been warming two and a half times faster than the prior estimates, which counters skeptical claims that global warming has “stopped.”

The new study covered data gaps over remote Arctic regions, which are warming faster than most of the planet, by using differences between satellite and ground temperature measurements, along with a well accepted — but previously unused — means of data interpolation to infill the gaps in data.

In doing so, Cowtan and Way found that global temperatures are continuing to rise at 0.12 degrees Celsius per decade, even while El Niño and La Niña natural variations offset some of the warming. They found that the Arctic is warming at 0.94 degrees Celsius per decade, almost eight times faster than the global average.

As more Arctic ice melts, more open water absorbs heat from the sun, rather than reflecting it into space, and warming speeds up in a positive feedback loop.

Warming the oceans leads to more powerful storms because typhoons, hurricanes and all tropical storms draw their vast energy from the warmth of the sea. The increased severity of these and other extreme events (such as droughts and wildfires) are consistent with global warming exacerbated by fossil fuel use.

So help us advocate for additional action by government to significantly reduce burning of fossil fuels. A fee on carbon dioxide emissions, with the revenue returned to the public, would enable a shift to renewable energy.

Many economists agree that this revenue-neutral, market-based fee and dividend on carbon dioxide emissions would be the fastest way to reduce our carbon footprints.

In the meantime, be careful. We’re on thinning ice.

Kathy D. Rand has a Ph.D. in biological sciences. Jim F. Chamberlain, Ph.D., P.E., is an environmental engineer. Michael J. Soreghan, Ph.D., is a geologist. Catherine Hobbs, Ph.D., is a professor of rhetoric and composition. All four live in Norman and are members of Citizens Climate Lobby in Norman.