What specifics could we imagine for observing Tisha B'Av in such a way as to grow political energy toward preventing climate disaster?
The basic rubric would be to see the Earth today as a Holy Temple in danger of destruction, as the Temples in Jerusalem were destroyed.
The Shalom Center is now developing a liturgy for Tisha B'Av that would embody this approach.
In regard to Washington, this is what I imagine doing: Gather anywhere between 50 and 1000 Jews (and others if they feel so moved) to gather at either or both the Capitol and White House, read all or part of Eicha (the Book of Lamentations) , interspersed with Kinot (laments) for the Earth, using the new liturgy.
In traditional observances, t'fillin are not put on in the morning, as a sign of mourning. They are then put on the afternoon, to move toward hope and celebration of the birth-time of Mashiach (Messiah).
Perhaps at Mincha time, therefore, the gathered community could turn toward drawing pictures (maybe by kids as well as grown-ups), singing songs, and creating other artful, oyful expressions of Mashiach-time.
Depending on what is happening at that time earth-wise on the Gulf Coast, in the Senate, etc., the gathering could present a petition focusing on specific demands/ proposals for healing the earth.
IF there is a "critical mass" of Washingtonians who will join in doing this, The Shalom Center will be glad to send out information on this , both inviting people from say, NYC to Virginia, to come to DC. (No halakha prohibits traveling on Tisha B'Av.)
We could also provide new liturgy to those who would prefer to do this in their own locales, perhaps at politically sensitive places like EPA or BP offices etc. or perhaps in their own congregations. (Writing letters to Congress or newspapers is also halakhically OK on 9 Av. )
Some participants in DC (or elsewhere) might feel moved to do nonviolent civil disobedience, others not. Some might observe the full Tisha B'Av fast, others not. Some might extend the no-food part of the fast beyond 9 Av. Some might want to visit specific Congresspersons. Etc.