Sometimes, states post on their websites their state’s specific policy on an international issue. Usually, these policies are found on the websites of more developed countries, and thus are easier to find, for example:
The “official Australian foreign policy on climate change” can be found by Googling that phrase, which will lead you to this site at the Department of Foreign Affairs and Trade, or click on this link if your country is Australia:
However, a similar search on the country of Belize produces this (probably less-than-helpful) website from the Ministry of Foreign Affairs:
Which is to say, your search results will be hit-and-miss; this particular strategy may or may not work well for you, completely contingent on the country you’re looking for and whether they have placed relevant information on their website(s).