the current state of climate science

Last November, the Climate Science Special Report (CSSR) was published. The CSSR “is designed to be an authoritative assessment of the science of climate change, with a focus on the United States, to serve as the foundation for efforts to assess climate-related risks and inform decision-making about responses.”

If you can navigate Twitter, click here to read this thread from scientist Katharine Hayhoe (when it pops up, just keep scrolling down the screen). Ms. Hayhoe provides very brief highlight of this 477 page report on what the science is telling us. The brevity and images really bring the message home.

(As an aside: Katharine Hayhoe is a climate scientist and Evangelical Christian.  She’s a tireless advocate for making climate science accessible via her YouTube channel, “Global Weirding.” She also travels around giving talks about how to talk about climate solutions without alienating folks in sub-populations that reject the prevailing science on anthropogenic global warming).

The conclusions are:

*”the past 115 years are now the warmest in the history of modern civilization… the last three years have been the warmest years on record for the globe

*”The global atmospheric carbon dioxide (CO2) concentration has now passed 400 parts per million (ppm), a level that last occurred about 3 million years ago

*”it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence
*”thousands of studies… have documented changes in surface, atmospheric, and oceanic temperatures; melting glaciers; diminishing snow cover; shrinking sea ice; rising sea levels; ocean acidification; and increasing atmospheric water vapor
*”A rise of as much as 8 feet by 2100 cannot be ruled out
*”There is broad consensus that the further and the faster the Earth system is pushed towards warming, the greater the risk of unanticipated changes and impacts, some of which are potentially large and irreversible.”

I highly recommend taking time to read the Executive Summary. The text is only 22 pages and takes about 40 minutes to read.

So, what does this mean?

The report very specifically avoided making policy prescriptions:

In accordance with this purpose, it does not include an assessment of literature on climate change mitigation, adaptation, economic valuation, or societal responses, nor does it include policy recommendations.”
In my mind, it means thus:

It means that we need to evaluate our institutions, behaviors, politicians, and organizations based on whether or not they help or hinder our transition to a low/zero-carbon human economy.

Alex Steffen has made some interesting prognostications around climate and energy policy, I’ll leave you with his piece (after, of course, you’ve read the executive summary from thousands of our top scientists).

The Smokestacks Come Tumbling Down: why momentum is building towards a snap forward in climate action


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