There is a common misunderstanding that there exists a Nobel prize of Economics; this was not included in Nobel's will, this prize was introduced by the Swedish National Bank, and the official name of the prize is Swedish National Bank's Prize in Economic Sciences in Memory of Alfred Nobel. In the similar way one could have made up new Nobel prizes, like one for mathematics and one for environmentalism. The Peace Prize has sometimes been awarded to environmentalists, but I believe it's an abuse of the institution (unfortunately, the Nobel Peace Prize is awarded by Norwegian politicians, hence the prize has become very much political - there are many people who should never have been awarded the prize).

For Mathematics there is the Abel Prize