A free hosted blog using the free Blogger.com or Wordpress.com is fine for just making known to the world your views about the environment, interacting with viewers, spread environmental awareness with perhaps Blogger.com being my choice over Wordpress.com
However, if you demands more from your blog like for selling environmentally friendly products, you would probably need to be able to do more than what Blogger.com and Wordpress.com can offer.
That is the circumstances which will require a shift to self hosted blog powered with Wordpress.org (yes, there are 2 versions of Wordpress, one free and hosted and another paid and require you to host yourself). This means you will have to choose a web host for your blog.
However, making a choice of webhost need not be a lonely affair as you have Web Hosting Rating for reading reviews of web hosts.
There are many web hosts which uses Windows webhosting because Windows users are more widespread.
However you also can choose Linux webhosing