Opinion editor's note: Editorials represent the opinions of the Star Tribune Editorial Board, which operates independently from the newsroom.
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The report last week that atmospheric levels of carbon dioxide are the highest they have been in human history was alarming — if that word can be applied to an alarm that has been sounding steadily for a long time.
Last April, U.N. Secretary-General Antonio Guterres said that the world is on a "fast track to climate disaster." Reports from the Intergovernmental Panel on Climate Change have regularly supported that assessment. NASA confirms that the past eight years are the hottest years on record.
All over the planet, in rich countries and poor, the consequences are clear and becoming clearer: floods in Germany and China, wildfires in the American West and Australia, rising sea levels that imperil coastal populations, heat waves that kill vulnerable people without the defense of air conditioning.
News about the earth's changing climate is so persistently bad that it's affecting mental health. It's reported to be a factor in suicides, both because its effects make people's lives miserable and because dread of the growing catastrophe begins to feel unbearable. A British expert on sustainability warned in a research paper that we had less than 10 years before climate-induced social collapse — and that was four years ago.
Carbon dioxide, the subject of the new report, is one of the gases that trap heat in the atmosphere. That triggers other effects, like reduced sea ice and the consequent warming of the oceans. Last week's announcement from the National Oceanic and Atmospheric Administration suggested that the level of CO2 measured in May — 421 parts per million — was about the same as the Earth experienced during the Pliocene Epoch more than 4 million years ago.
That's about 2 million years before humans appeared and started making stone tools. Sea levels were higher then, and temperatures were hotter. Conditions were much less hospitable to human life, but that hasn't stopped humanity from risking a return to the bad old days.