375 climate scientists warn about the 2016 Presidential race

Today, 375 members of the National Academy of Sciences released an open letter warning about dangerous consequences if the next U.S. President pulls out of the Paris climate agreements.

The unprecedented letter warns:

"that the problem of human-caused climate change is real, serious, and immediate, and that this problem poses significant risks: to our ability to thrive and build a better future, to national security, to human health and food production, and to the interconnected web of living systems."

The letter is signed by many of the world's leading climate scientists. It represents a clear and dire warning from scientists to politicians: The earth is on the verge of a tipping point where increasingly severe physical, human and economic shock waves from climate change are imminent.

Here's more from the text of the letter.

On September 20, 2016, 375 members of the National Academy of Sciences, including 30 Nobel laureates, published an open letter to draw attention to the serious risks of climate change. The letter warns that the consequences of opting out of the Paris agreement would be severe and long-lasting for our planet’s climate and for the international credibility of the United States.

Our fingerprints on the climate system are visible everywhere. They are seen in warming of the oceans, the land surface, and the lower atmosphere. They are identifiable in sea level rise, altered rainfall patterns, retreat of Arctic sea ice, ocean acidification, and many other aspects of the climate system. Human-caused climate change is not something far removed from our day-to-day experience, affecting only the remote Arctic. It is present here and now, in our own country, in our own states, and in our own communities.

During the Presidential primary campaign, claims were made that the Earth is not warming, or that warming is due to purely natural causes outside of human control. Such claims are inconsistent with reality.

From studies of changes in temperature and sea level over the last million years, we know that the climate system has tipping points. Our proximity to these tipping points is uncertain. We know, however, that rapid warming of the planet increases the risk of crossing climatic points of no return, possibly setting in motion large-scale ocean circulation changes, the loss of major ice sheets, and species extinctions. The climatic consequences of exceeding such thresholds are not confined to the next one or two electoral cycles. They have lifetimes of many thousands of years.

The political system also has tipping points. Thus it is of great concern that the Republican nominee for President has advocated U.S. withdrawal from the Paris Accord. A “Parexit” would send a clear signal to the rest of the world: "The United States does not care about the global problem of human-caused climate change. You are on your own." Such a decision would make it far more difficult to develop effective global strategies for mitigating and adapting to climate change. The consequences of opting out of the global community would be severe and long-lasting – for our planet’s climate and for the international credibility of the United States.

Ben Santer and Kerry Emanuel, two of the lead authors of the letter, go further in this piece in the Washington Post, warning of "dangerous" consequences if the Paris agreement is abandoned by the next U.S. President.

Scientists know climate change is a threat. Politicians need to realize it, too.

The climate is changing in dangerous ways, and we are responsible for most of these changes. This is not a matter of conjecture or political opinion — it is the conclusion of the overwhelming majority of climate scientists, based on solid evidence that mounts each year. Rising sea levels, extreme heat, increased incidence of floods and drought, ocean acidification and expansion of tropical diseases pose an unacceptable level of risk to our descendants. So do many other climate-related threats.

Both Santer and Emanuel have been guests on MPR's Climate Cast. We've also interviewed several of the other signers on Climate Cast in the past.

News of today's is likely to reverberate through the news and climate communities in the coming weeks.