On May 9 Hawaii's Mauna Loa Observatory recorded carbon dioxide (CO 2 ) levels of 400 parts-per-million (ppm). Scientific American reports that when measurements started in 1958, "the daily average could be as low as 315 ppm, already up from a pre-industrial average of around 280 ppm."
Scientists believe that Earth hasn't had these levels since the Pliocene era 3 to 5 million years ago. At that time temperatures were 5.4 to 7.2 degrees F warmer than now, and sea levels were 16 to 131 feet higher than today.
A major cause of global warming is consumption of fossil fuels (coal, oil and natural gas). When burned, these fuels emit carbon dioxide, which made up 84% of greenhouse gases emitted by the U.S. in 2011.
Increasing heat waves, droughts, severe storms, forest and grass fires, flooding of river basins and coastal areas, declining crop production, rising sea levels that threaten coastal cities and infrastructure: all this and more is looming for the U.S. and much of the planet as a result of rising global temperatures.
In 2009 the National Academies of Science of the 13 wealthiest nations proclaimed in a joint statement that "climate change is happening even faster than previously estimated," and "the need for urgent action to address climate change is now indisputable."
Our national-security officials get it. The Department of Defense's environmental science division warns that "sea level could increase by roughly up to 1 meter by 2100 and by 2 meters if Greenland ice sheet melt accelerates." (The ice sheet melted at a record rate in the summer of 2012.)
It should be obvious that we need a national commitment to sharply reduce our use of fossil fuels and rapidly develop technology for renewable non-polluting energy such as solar, wind, and geothermal power.
The Obama administration has taken some modest steps to reduce carbon pollution. For instance, it released new fuel-economy standards last summer, requiring automakers to raise the average fuel efficiency of new cars and trucks to 54.5 miles per gallon by 2025. GOP presidential nominee Mitt Romney promptly vowed to overturn this standard if elected. During the primaries, every GOP presidential candidate except Jon Huntsman dismissed the dangers of climate change.
Congressional Republicans respond to scientists' warnings with skepticism or outright denial, and are totally opposed to doing anything about global warming. A good example of this intransigence is Sen. James Inhofe (R-Oklahoma). He's the senior Republican on the Senate Committee on Environment and Public Works (which he chaired from 2003 to 2007).
His book The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future appeared in February 2012. Some hoax! All those national academies of science taken in by it!
In 2010 Stanford researchers compiled a list of scientists who had published at least twenty papers on climate. They found that 97-98% of the top 200 scientists (ranked by frequency of publication) agree that global warming is accelerating, and that human activity is the principal cause.
Inhofe has two sources for his certainty about the "hoax": God and Mammon. In a radio interview with Voice of Christian Youth America (3/8/12), he explained that his book is biblically inspired:
"The Genesis 8:22 that I use in there is that "as long as the earth remains there will be 'seed time and harvest, cold and heat, winter and summer, day and night,' my point is, God's still up there. The arrogance of people to think that we, human beings, would be able to change what He is doing in the climate is to me outrageous."
In addition to divine support, Mammon chipped in with about $1.5 million from oil and gas industries in 1989-2012.
The recently appointed chairman of the House Science Committee is Lamar Smith (R-Texas). He refers to concerned climate scientists as "global warming alarmists."
A group of very wealthy conservatives have bought some intellectual support for climate-change denial. As The Guardian (2/15/13) reports, "Donors Trust and Donors Capital Fund," secretive conservative bundlers, have for a decade "channelled nearly $120m to contrarian thinktanks and activists" that give the appearance of scientific respectability to deniers in Congress.