A historic landmark occurred last week. Scientists at a Hawaii mountaintop observatory reported that carbon dioxide buildup in the atmosphere reached 400 parts per million for the first time since the Pliocene Epoch — 5 million to 3 million years ago, long after dinosaurs died, but before early humans evolved.
Before the Industrial Revolution, atmospheric CO2 had averaged about 280 ppm for at least 800,000 years. But an upsurge of coal, oil and gas burning began a relentless increase in the “greenhouse gas” that forms a heat-trapping barrier in the sky, slowly warming the planet’s surface.
If the CO2 buildup keeps climbing past 450 ppm, it may cross a “tipping point” that will trigger the worst dangers of global warming. Arctic ice will melt, raising sea levels and flooding many coastal cities. Storm severity will worsen, inflicting trillion-dollar nightmares akin to last year’s Superstorm Sandy. Floods, droughts, wildfires, tropical diseases and other evils will torment humanity. Losses will be enormous.
So far, humanity shows little desire to reduce fossil fuel burning. Appalachia’s coal reserves are near an end, but natural gas is surging and oil remains a pillar of the world economy. The U.S. Geological Survey proudly reported this month that oil and gas deposits under western states may be twice as high as former estimates.
One more dreary fact: Methane leaking into the sky by the gas-drilling boom and by melting of arctic tundra is an even worse greenhouse gas than carbon dioxide.
Most people don’t notice that a slow-motion calamity already has started. But unless global warming is curtailed by a rapid expansion of renewable energy — solar, wind, tidal, geothermal, biomass, etc. — the entire world eventually will feel painful results.
— Distributed by The Associated Press