Geography vs. PPE at Oxford

Hi,

With October fast approaching, I really need to choose the degree I would like to study. However, I can't decided between PPE or Geography (hopefully both at Oxford). Is Geography at Oxford as rigorous and / or mathematical as PPE? How are the employment prospects? Does Geography have a lot of politics or international relations aspects to it?

I like the look of PPE but I have an interest in environmental research. If there was a way for me to take PPE and then do a PhD in environmental research, I would take PPE. Any hope?

Thanks in advance.