Climate Signals Summary: Since the late 1970s, scientists have known that global warming is underway due to the increase in greenhouse gases from human activities. 2010-2019 was the hottest decade ever recorded, and 2016 was the hottest year.
Article Excerpt: Last month tied for the warmest April on record for the globe, as 2020 hurtles toward the warmest year milestone.
New data, released Tuesday from the European Union’s Copernicus Climate Change Service, lends further support to the prediction that 2020 will rank among the top two warmest years recorded.
Human-caused climate change from increasing amounts of planet-warming greenhouse gases is vaulting temperatures higher, making it easier for a given month or year to set a new warmth milestone. Carbon dioxide is the most important long-lived greenhouse gas in the atmosphere, released by the burning of fossil fuels such as coal and oil for energy and transportation.
Daily carbon dioxide levels measured at the summit of Mauna Loa in Hawaii have reached 418 parts per million this month, the highest level in at least 3 million years. It’s expected that the monthly average value for 2020 will be set this month, and will be near 417 ppm, compared with last year’s measurement of 414.7 ppm.
The Great Barrier Reef, a World Heritage Site, suffered its biggest coral bleaching event on record in 2020 as a marine heat wave gripped the 1,400-mile-long biodiversity hot spot.
That 2020 may eclipse 2016 for the dubious title of the warmest year on record is another indication of human influence on the climate.
Currently, there is no declared El Niño event in the tropical Pacific Ocean, which tends to provide a natural boost to global temperatures that are already elevated because of the human-caused buildup of greenhouse gases in the atmosphere. By contrast, the 2016 record occurred during an extremely strong El Niño event.
Assuming NOAA ranks April as having global average temperatures above the 20th-century average, it would be the 424th straight month to have that distinction.
In other words, those who are 35 years old and younger have never experienced a cooler-than-average month on Earth.