August 2015 Newsletter

In this Clergy Letter Project update, you’ll find the following six items:

  1. Evolution Weekend 2016;;
  2. Astrobiology News for August 2015:  “Slushball” Earth;"
  3. Extending Summer Vacation for Creationism?;
  4. Good News from Canada;
  5. United Methodist Church / Clergy Letter Project News; and
  6. Michael Zimmerman on the Road and Other Possible Speakers.

1. Evolution Weekend 2016

Even though Evolution Weekend 2016 (12-14 February 2016) is still approximately a half a year away, the number of congregations signing up to participate is growing very nicely. As of today, more than 120 congregations representing 32 states and 8 countries have already signed up to participate. If you haven’t yet done so, why not sign up today! All you need to do is let me know who you are and hit reply. I’ll do the rest.

_____ YES, I plan to participate in Evolution Weekend 2016, 12-14 Feb. 2016. Please add me to the list!

Your name:

Although our list of participants for Evolution Weekend 2016 is not yet public, you can look at it by clicking here. If you are already on the list, you don’t need to do anything. If you’re not yet listed, please let me know and I’ll add you immediately.

Finally, please remember that the purpose of Evolution Weekend is to improve the quality of the dialogue about the relationship between religion and science. How you opt to do that is fully up to you: Anything you deem appropriate IS appropriate. Deliver a sermon, host a lunch discussion, watch a video, publish something in your weekly bulletin – all are acceptable activities. And remember if this particular weekend doesn’t work for you, that’s ok as well. If you plan to engage in an activity that advances our understanding of religion and science, whenever you can do it is great. Let me know and I’ll get you added to our list. Thanks for signing up now.


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2. Astrobiology News for August 2015:  “Slushball” Earth

In this month’s Astrobiology News, Clergy Letter Project consultant and Adler Planetarium astronomer Grace Wolf-Chase discusses explores long term climate change on the planet. As she discusses, this work helps us investigate the past, predict the future and understand the possibilities for discovering other habitable worlds.

I’d planned this month’s news to be about the Dawn mission at asteroid/dwarf planet Ceres, but I’ll postpone that article until we get further results. Instead, I’ll share some recent research into the evolution of Earth’s climate that’s relevant to all denizens of our planet! Global climate models that predict where our planet is heading in the future can also be used to explore where it’s been in the past. Such models indicate that the Earth has gone through several periods of runaway glaciation resulting in a “Snowball Earth,” with global, or near global, ice cover. The principal evidence for these periods comes from geologic evidence of glaciers near the equator. Ice reflects about 55-80% of incoming sunlight (much more than either ocean water or land), sending that energy back into space rather than warming the planet, so more ice cover leads to lower temperatures which lead to more ice and even lower temperatures, possibly until the entire planet is frozen.

At least two of these Snowball Earth periods are associated with the Cryogenian period, which lasted from 850-635 million years ago. One big conundrum with the frozen Earth scenario during this period has been how the Earth managed to warm up. Once covered with ice, the positive feedback loop that leads to further cooling presents a problem for thawing the Earth. Also, there is no evidence for a mass extinction event during this period, nor is there geological evidence to support a great release of greenhouse gases into Earth’s atmosphere due to volcanic activity that could warm the planet. However, there is evidence for an ongoing water cycle, rather than the dry atmosphere that would develop if the oceans were completely frozen over.

Columbia University geologist, Linda Sohl,(1) and her colleagues have focused on modeling the Cryogenian period including important parameters in their models such as the brightness of the Sun (it was about 6% dimmer than it is today) and the arrangement of the continents into a single supercontinent near the equator.

The goal of this research is to identify the factors most important in driving glaciation or halting it. They have found that ocean circulation seems to prevent a complete freeze, and their models predict about half of the oceans remain ice-free, resulting in more of a “Slushball” than “Snowball” effect. One of the most outstanding issues remaining in these studies may be the effect of topography; that is, altitude variations that could affect glaciation.

In addition to being critical to understanding Earth’s evolutionary past, these computer models are important to discussions on the limits of habitability on planets orbiting other stars. A world of solid ice would not be very hospitable to life forms dependent upon liquid water! Might water-bearing planets like Earth carry some “natural defense mechanism” against global freezing? If so, planetary environments containing liquid water may be more common than Astrobiologists have traditionally assumed. Check out to keep up with some of the latest Astrobiology research!

Until next month,


Grace Wolf-Chase, Ph.D. (

1. See


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3. Extending Summer Vacation for Creationism?

Our good friends at the National Center for Science Education report on two bills likely to be introduced in Kentucky to prohibit public schools from starting “earlier than the first Monday closest to Aug. 26.” The reason? Simple. The proposers of the bill want to ensure a steady stream of tourists to the Answers in Genesis theme park under construction: Ark Encounter. As Damon Thayer (R-District 17), one of the prospective sponsors said, "Grant County is set to become a major tourist destination due to the presence of the Ark."


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4. Good News from Canada

The Vancouver Observer reports that a large majority of Canadians in British Columbia are not supportive of creationism. The article entitled “BC evolving away from Creationism” noted “that 72 per cent of residents think human beings evolved from less advanced forms of life over millions of years. The notion that God created human beings in their present form within the last 10,000 years is endorsed by just 17 per cent of British Columbians. The proportion of creationists climbs to 27 per cent among people who reside in the North and the Southern Interior, but drops to 16 per cent in Metro Vancouver and nine per cent in Vancouver Island.” If only the United States could boast numbers of that sort.


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5. United Methodist Church / Clergy Letter Project News

I’m delighted to say that two United Methodist Church Conferences recently passed resolutions endorsing The Clergy Letter Project. The first, spearheaded by Clergy Letter Project member Gary Sherman, was adopted by the Baltimore-Washington Annual Conference. That petition calls for the 2016 General Conference to renew its support for The Clergy Letter Project and Evolution Weekend.

The second petition was organized by Clergy Letter Project member Reverend David Felton and was adopted by the Desert Southwest Conference. It too fully endorses The Clergy Letter Project and calls for members to participate in Evolution Weekend.

This showing of support is wonderful. I hope you all join me in thanking both Gary and David for their efforts.


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6. Michael Zimmerman on the Road and Other Possible Speakers

Members often ask me to let them know when I’ll be traveling so they might invite me to speak when I’m in their part of the country. For that reason, I wanted to let people know about three upcoming trips:

Bellingham, WA from 2 October 2015 – 4 October 2015
St. Louis, MO from 29 October 2015 – 1 November 2015
Washington, DC from 20 January 2016 – 24 January 2016

If you’d like to explore the possibility of inviting me to speak, please contact the good folks at Ovation Agency. Make sure that they know you’re associated with The Clergy Letter Project and they’ll reduce their fees dramatically. Additionally, they have a number of other fabulous speakers who would love to speak about the intersection of religion and science. Check out their web pages and see about issuing an invitation. I know you won’t be disappointed.


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Let me close this month by thanking each of you for your continued support.  And let me ask you to think about finding a friend with whom you can share this newsletter.  Together we are making a difference.


Michael Zimmerman
Founder and Executive Director
The Clergy Letter Project