In the big picture of the global warming epidemic, we often forget that greenhouse gases hurt more than just our atmosphere temperatures. Global warming includes ocean warming – a phenomenon that can alter the marine food chain, results in ocean acidification and threatens Antarctic wildlife by potentially endangering populations of penguins, whales, seals and a host of smaller creatures within a few decades. And while mankind may not want to accept blame for what goes on under the sea, the scientific evidence suggests otherwise.
A recent study (titled ”Human-Induced Global Ocean Warming On Multidecadal Timescales“) published in Nature Climate Change found that humans are, in fact, to blame for the warming of oceans. The study was conducted by researchers in four countries (U.S., Australia, Japan and India) and analyzed estimates of ocean temperatures of the years to determine the cause of the warming of our oceans. What did they find? They found that the observed global average ocean warming, from the surface to 700 m, is approximately 0.025°C per decade – or slightly more than 1/10th of a degree Celsius over 50 years. The study concluded that the only plausible explanation for ocean warming can be found when greenhouse gas increase is included into the equation.
Lead author and LLNL climate scientist Peter Gleckler stated in a a Lawrence Livermore National Laboratory press release:
“The bottom line is that this study substantially strengthens the conclusion that most of the observed global ocean warming over the past 50 years is attributable to human activities. Although we performed a series of tests to account for the impact of various uncertainties, we found no evidence that simultaneous warming of the upper layers of all seven seas can be explained by natural climate variability alone. Humans have played a dominant role.”
The best way to see the future of ocean warming is to see the current state of atmospheric warming, since the ocean warms as a result of atmospheric temperature changes. One quick look at the state of atmospheric warming and it is easy to see that the future of the ocean is not bright. Scientists have monitored stations across the Arctic and have been recently finding that there are more than 400 parts per million of heat-trapping gas in the atmosphere. The last time our planet saw carbon dioxide levels this high is 800,000 years ago, according to the scientists. They’re quick to acknowledge that the shock isn’t from the quantitative value, but instead, the surprise is how quickly this value is accelerating.
The increase in carbon dioxide levels can be credited to man-made causes, mainly burning fossil fuels. And the proof is in the numbers: Prior to the Industrial Age, when carbon dioxide came from natural sources like decomposing plants and animals, the levels were about 275 part per millions. But since the Industrial Revolution in the 1700′s, activity by man (e.g., burning of oil, coal and gas, and deforestation) has taken a key part in increasing the CO2 concentrations in the atmosphere.
Oceanography expert Nathan Bindoff told Australia’s ABC News AM, ”This paper’s important because, for the first time, we can actually say that we’re virtually certain that the oceans have warmed, and that warming is caused not by natural processes, but by rising greenhouse gases primarily.” He added, “We did it. No matter how you look at it, we did it. That’s it.”
Photo by Nomadic Lass on Flickr