This is going to sound pessimistic at first but hear me out: Unless you're extremely gifted in many ways and super resourceful, you're not likely to make any noticeable impact on the species.
However, you can still make a big difference for groups much smaller than the whole species (and I think that's actually preferable from a human point of view because it's more tangible). The world is full of problems that could easily be solved by good software. This is especially true in industries that are usually not very technological by themselves.
Depending on your current network you might have gotten to know an industry or two that is not strictly technological. If not, ask your friends who do not program software all day and ask them what problems they have at work that they find annoying and try to come up with a software solution for that.
Once you do that, convince their bosses that it saves them more money to pay for your software than to do things the old way.
I wouldn't be so pesimistic. We started an organisation that builds open source cloud data systems used among other things to track drinking water infrastructure and sustainable food production in Africa and Asia. We started from scratch and we now work with 20+ governments, 200+ NGOs and several UN organisations. We are probably not extremely gifted, but more like middle of the road startup geeks. Still we make an impact.
However, you can still make a big difference for groups much smaller than the whole species (and I think that's actually preferable from a human point of view because it's more tangible). The world is full of problems that could easily be solved by good software. This is especially true in industries that are usually not very technological by themselves.
Depending on your current network you might have gotten to know an industry or two that is not strictly technological. If not, ask your friends who do not program software all day and ask them what problems they have at work that they find annoying and try to come up with a software solution for that.
Once you do that, convince their bosses that it saves them more money to pay for your software than to do things the old way.