For the first time since human existence, on May 9, carbon dioxide levels in Earth’s atmosphere reached 400 PPM. There are now 400 molecules of CO2 for every million molecules of air, but this number is not limited to a literal meaning. We have reached a “grim milestone,” but levels are still on the rise. Scientists and environmental advocates alike call for reform, but as we know, effective reform is never easy.
Global CO2 levels in 2012 proved that nations across the globe must cooperate to lower emissions. Although the U.S. succeeded in lowering CO2 emissions by 13% in the last several years, the worldwide levels were the highest ever recorded.
The Mauna Loa observatory has monitored CO2 levels since 1958, but air bubble samples from ice sheets in the Antarctic prove CO2 has not reached these levels in the past 800,000 years. One recent scientific paper suggests that the last time CO2 levels were similar to what they are now was 10 to 14 million years ago.
Carbon dioxide levels do fluctuate, and May is peak CO2 season, but just because levels will drop slightly until October (annual minimum) does NOT mean that levels will not continue to increase.
Many suggest extreme action is the only solution. According to James Hansen, renowned NASA scientist, the world would have to stop burning coal for any hope of returning CO2 levels to 350 PPM. One reason why this is such a “grim milestone” is because the damage caused by CO2 is irreversible, at least for the next 1000 years. Especially problematic is the projected sea level rise and decrease in rain fall in several regions of the world, potentially creating “dust bowls.”
The issue of atmospheric rise in CO2 carries over into our oceans. The ocean absorbs as much as 25% of the CO2 that enters the atmosphere each year. This could be seen as a benefit to terrestrial life, however it is extremely detrimental to ocean life. The addition of CO2 results in the production of bicarbonate ions, causing a phenomenon known as ocean acidification.
The pH of the surface of the ocean has dropped 0.1 units since the 18th century. This change may seem small, but keep in mind that the pH scale is logarithmic, meaning the ocean has become 30% more acidic. This has a number of negative impacts on the ocean, including coral reef bleaching.