Great news, everyone! We’re getting better at measuring the changing temperature of the ocean. Unfortunately, the data shows that they are warming more rapidly than researchers thought.
A new study published in Scientific Advances has pulled together the data we have for ocean heating from 1960-2015. It provides what is believed to be the most accurate account of the changes that the oceans have experienced over those 45 years. Among the authors’ findings: The oceans are warming 13 per cent faster than was previously believed.
Part of the reason our previous estimations were off was the difficulty of reconciling the pre- and post-2005 data. That year, scientists began using the Argo float system to make measurements. Capable of reaching depths of up to 2000 feet, the Argo system has been superior to the bathythermographs that were widely used before. Rather than having sensors laid out along major shipping lines and primarily in the northern atmosphere, we now have around 3500 floats scattered throughout the world. These floats can dive below and rise above on their own and give us more complete, accurate data.
First, we corrected past data for known biases in measurements. Second, we related the temperature measurements to results calculated from advanced climate computer models. Third, we applied temperature knowledge to larger areas so that a single measurement was representative of a large space around the measurement site. Finally, we used their knowledge of recent and well-observed temperatures to show that the method produced excellent results.
We were able to extend our techniques back to the late 1950s and show that the rate of global warming has changed significantly in the past 60 years. One main outcome of the study is that it shows we are warming about 13% faster than we previously thought. Not only that but the warming has accelerated. The warming rate from 1992 is almost twice as great as the warming rate from 1960. Moreover, it is only since about 1990 that the warming has penetrated to depths below about 700 meters.
This is a big deal within the field of climate change. More than 90% of the extra heat generated by carbon dioxide makes its way to the oceans in the end. That makes them a great place to analyse increasing temperatures. It’s also extremely worrisome because if temperatures continue to increase, and ice continues to melt, some areas of the world could see sea levels rise up to 200 feet.
What’s also interesting about this study (and kind of poetic) is what the team refers to as the oceans containing “the memory of climate change.” Essentially, what they mean is the rising temperatures are spreading deeper and further between the oceans. Despite changing weather patterns offering details that could indicate cooling in certain areas, the overall atmosphere is warmer and more moist than in previous years. This is understood to be responsible for more intense rains and storms all around the globe. Not to mention the heat waves, droughts, wild-fires and other consequences that arise from climate change.
As the data becomes more precise and is reconciled with older information, it only seems to indicate things are worse than we had assumed. The estimated point of no return only gets closer with each passing year. Finding out that it was probably closer than we realised in the first place is unnerving, to say the least. [The Guardian]