Rising temperatures can be recorded in the late 1950s, with the last five years being the five hottest on record
Last year was the hottest ever measured, continuing an upward trend that is a direct result of man-made greenhouse gas emissions.
The key to measurements is the oceans. The oceans absorb more than 90% of the heat generated by greenhouse gases, so if you want to measure global warming, you really have to measure ocean warming.
There are other ways to measure climate change, but none are as convincing as the oceans. Air temperatures are most commonly reported in the media as evidence of global warming, but the problem with this is that they are very erratic. While there is a long-term trend of higher air temperatures, any year can be warmer or colder than the previous one.
So the oceans are key, and they are telling us a clear story. The last five years were the hottest five. The numbers are huge: in 2018, additional ocean heat compared to a 1981-2010 baseline amounted to 196,700,000,000,000,000,000,000 joules. The current rate of ocean warming is equivalent to five Hiroshima-sized atomic bombs exploding every second.
The measurements were published in the journal Advances in Atmospheric Sciences in an article by Lijing Cheng, the lead author, and his colleagues at the Institute of Atmospheric Physics in China. His collaborators, of whom I am one, included researchers from around the world. The article records the ocean's heat up to the late 1950s, showing a steady increase.
Ocean warming is incontrovertible proof of global warming, and there are real consequences for ocean warming.
First, warmer water expands, and this expansion causes sea levels to rise. About a third of the increase in ocean waters is the result of heat absorbed by the oceans. Scientists expect a rise of about a meter in sea level by the end of the century, which would be enough to displace 150 million people worldwide.
Warming waters also make storms more powerful. Recently in the US, we have seen hurricanes passing over extremely warm ocean waters, overloading them and increasing the damage they do. Other types of storms are getting stronger as well. More torrential rains are increasing flooding around the world. Simply put, our greenhouse gas emissions have caused loss of life and property. We are all responsible, but people who have denied science and solutions have a special responsibility that history will judge harshly.
Not only humans are suffering and will suffer more in the future. Warming oceans are causing tremendous problems for marine life, particularly coral reefs. If we continue to warm the planet, we can expect to lose much of these reefs. We can also anticipate reductions in fish and marine life populations.
We scientists look like a broken record. Every year we introduce science and advocate for action. Not enough is being done. We can still deal with climate change, but we must act immediately. We have the means to make a difference, we just lack the will.
Original article (in English)