For the first time since accurate measurements of carbon dioxide have been taken, the amount in the atmosphere has topped 400 parts per million (ppm) for a sustained period. Many climate scientists, such as James Hansen of NASA's Goddard Institute, believe that any sustained period of time with higher than 350 ppm threatens catastrophic global warming.
Since 1992, when many countries pledged to reduce carbon dioxide emissions at the Rio Summit, emissions have been steadily increasing. As more dire warnings from scientists have accumulated, as more extreme weather events have forced awareness of climate change, carbon dioxide in the atmosphere has continued to increase. In many years emissions have accelerated instead of being reduced, as virtually all scientific authorities have called for and as most major industrial countries have pledged to do.
Carbon dioxide emissions accumulate in the atmosphere, meaning that current emissions will continue to affect our weather and climate systems for many decades, even centuries. The earth's climate system is massive, and like massive ocean liners, it takes a long time to make it change course. The climate changes we are currently experiencing result from the last 150 years of accumulation and increases, resulting from industrial development, transportation, other burning of fossil fuels, and deforestation.
Recent public opinion polls continue to show a large majority understanding that climate change is real (though the exact percentage continues to fluctuate up and down with media coverage and extreme weather events), and a plurality of people who know that it is caused by human activity. Many people have been affected by the climate change deniers and their campaign to confuse understanding and delay action. Well over 90% of climate change scientists and climate change peer-reviewed publications confirm the scientific understanding that climate change is real, it is primarily caused by human activity, and it is getting worse.
Many major corporations desire to keep making money from business as usual, in spite of how destructive to our common future that will be. And they desire, if action is taken, to place the burdens and costs of change on workers and communities, rather than on those who have been making excess profits from polluting our atmosphere. They want to keep atmospheric pollution as an "externality" that they don't have to include on their balance sheets.
Many of the same corporations and business interests who promote climate change denialism also oppose union rights, increases in the minimum wage, and health care for all. The Koch brothers, who fund much right-wing political activism, are prime examples. They understand that just as stronger unions threaten their profits, so too does serious action to address climate change.
Even as some countries take real action to reduce greenhouse gas emissions (Germany, for example), the situation is getting worse. Fueled by new coal-fired electric plants in China and India, by deforestation in the Amazon, Indonesia, and Siberia, by growing numbers of gas-fueled cars, by continuing subsidies to fossil fuel industries, and by petroleum-based agriculture, we are pushing ever closer to dangerous tipping points which threaten to spiral the world's climate systems out of control.
The potential exists for millions of new jobs in the U.S., converting to solar-based energy, retrofitting existing buildings, and building sustainable agriculture. This could lay the basis for a new unity between the labor movement, the environmental movement, and all progressives.
A dramatic turn is necessary - as the new high of carbon dioxide in the atmosphere highlights. Without such a shift, the earth is in danger of even more harmful extreme weather events, including prolonged multi-year drought in many places. The threat is not to the existence of the earth, it is to the possibility of a flourishing humanity. Already there are millions of climate refugees, millions of people harmed by extreme weather such as Hurricane Sandy and the drought in much the U.S. Mid-West and Southeast, millions facing increased water stress. These are no longer theoretical or in the future, they have already arrived.
400 ppm is a clarion call for action, for transforming our building, industrial, transportation, distribution, agriculture, and water systems. A healthy humanity depends on a health earth, and 400 ppm is the planet's rising temperature. The earth has a fever, and humanity will pay the price.
Photo: This December 1972 file photo released by NASA shows a view of the Earth as seen by the Apollo 17 crew while traveling toward the Moon. The photograph extends from the Mediterranean Sea and Africa, top, to the Antarctic polar ice cap, made visible for the first time by the Apollo trajectory. (AP Photo/NASA)