Environmental Economics

From the Typepad helpdesk:

Thanks for contacting us, and we apologize for the problem you
encountered. We are currently investigating the issue with not being
able to sign in to comment impacting some blogs. This issue impacts all
browsers. The reason you were able to sign in via Internet Explorer is
likely due to the selection of the "Remember Me" option which has been
found as a workaround for the bug.

Until we release a fix, you do have some options to workaround the
issue. The quickest solution for you and your commenters is to enable
Typepad Connect comments. The sign in bug only impacts blogs using the
default commenting system. At Settings > Comments, you can scroll down
to the end of the list and click to enable Typepad Connect comments.
Then, you will be able to sign in to comment without issue.

You can also remove the option to sign in to comment if you prefer. At
Settings > Comments, set the Comment Authentication setting to No and
click Save Changes. This will remove the sign in options and allow
comments to be submitted without signing in.

We are sorry for any inconvenience caused by this issue. As soon as we
have more details about the resolution of the sign in problem for
comments, we will let you know.

In the meantime, please let us know if you have any questions.

So, I clicked on the Typepad Connect (beta) comments box and am told:

Congratulations! You’ve successfully enabled TypePad Connect comments for your TypePad blog.

If it doesn't work, please let me know in the comments section.