Add climate action note to README

README.md

@@ -138,6 +138,7 @@ the final result in whatever units you want.
     - [Understanding quantity types](#understanding-quantity-types)
   - [Getting help](#getting-help)
   - [API](#api)
+  - [Climate action](#climate-action)
   - [Contributing](#contributing)
   - [License](#license)
 
@@ -457,6 +458,22 @@ or posting on the [Elm Discourse forums][4] or the [Elm subreddit][5]. I'm
 
 [Full API documentation][10] is available.
 
+## Climate action
+
+I would like for the projects I work on to be as helpful as possible in
+addressing the climate crisis. If
+
+- you are working on a project that helps address the climate crisis (clean
+  energy, public transit, reforestation, sustainable agriculture etc.) either as
+  an individual, as part of an non-profit organization or even as part of a
+  for-profit company, and
+- there is a new feature you would find helpful for that work (or a bug you need
+  fixed) in any of my open-source projects, then
+
+please [open a new issue](https://github.com/ianmackenzie/elm-units/issues),
+describe briefly what you're working on and I will treat that issue as high
+priority.
+
 ## Contributing
 
 Yes please! One of the best ways to contribute is to add a module for a new