Yes, we’ve heard this before, again, and again, and again. Further, I’m not sure this fellow qualifies as a “Top Climate Scientist”.
From some website called GritPost:
Top Climate Scientist: Humans Will Go Extinct if We Don’t Fix Climate Change by 2023
A top climate scientist is warning that climate change will wipe out all of humanity unless we stop using fossil fuels over the next five years.
In a recent speech at the University of Chicago, James Anderson — a professor of atmospheric chemistry at Harvard University — warned that climate change is drastically pushing Earth back to the Eocene Epoch from 33 million BCE, when there was no ice on either pole. Anderson says current pollution levels have already catastrophically depleted atmospheric ozone levels, which absorb 98 percent of ultraviolet rays, to levels not seen in 12 million years.
Anderson’s assessment of humanity’s timeline for action is likely accurate, given that his diagnosis and discovery of Antarctica’s ozone holes led to the Montreal Protocol of 1987. Anderson’s research was recognized by the United Nations in September of 1997. He subsequently received the United Nations Vienna Convention Award for Protection of the Ozone Layer in 2005, and has been recognized by numerous universities and academic bodies for his research.
While some governments have made commitments to reduce carbon emissions (Germany has pledged to cut 95 percent of carbon emissions by 2050), Anderson warned that those measures were insufficient to stop the extinction of humanity by way of a rapidly changing climate. Instead, Anderson is calling for a Marshall Plan-style endeavor in which all of the world takes extreme measures to transition off of fossil fuels completely within the next five years.
Recovery is all but impossible, he argued, without a World War II-style transformation of industry—an acceleration of the effort to halt carbon pollution and remove it from the atmosphere, and a new effort to reflect sunlight away from the earth’s poles.
This has do[sic] be done, Anderson added, within the next five years.
“The chance that there will be any permanent ice left in the Arctic after 2022 is essentially zero,” Anderson said, with 75 to 80 percent of permanent ice having melted already in the last 35 years.
Anderson’s prediction of Arctic sea ice disappearing by 2022 may be closer to reality than a lot of us would hope. In 2016, University of Reading professor Ed Hawkins compiled global temperature data dating back to 1850, prior to the Industrial Revolution of the early 20th century and the oil boom, and turning the data into a time-lapse GIF. The most alarming part of the data showed that temperatures began rising exponentially faster at the start of the 21st century and show no signs of slowing down:
— Ed Hawkins (@ed_hawkins) May 9, 2016
Full story here if you want to bother with it.