Bill Gates certainly isn’t the only rich philanthropist, but he has poured himself into the work in a way that others haven’t. After he stepped back from the day-to-day operations at Microsoft Corporation (NASDAQ:MSFT) (though he is still involved with the company he founded), Gates devoted himself to running the Bill and Melinda Gates Foundation, which tackles everything from child mortality rates to designing better condoms.

bill gates

He’s spent enough time working on the issues facing the most impoverished nations on earth, including Yemen and Somalia, that he has a realistic sense of the challenges facing the planet. But as becomes clear in a wide-ranging interview that Gates did with Jeff Goodell for Rolling Stone recently, he is still very much an optimist.

One of Gates’ major initiatives has been to eliminate polio, and he has made incredible progress, eradicating the disease in India and many other developing countries. Most of the remaining strongholds are in countries where political forces make it difficult to safely administer the vaccine on a large scale, such as North Korea and parts of Pakistan. The disease has even come back in Somalia and Syria, both extremely unstable countries, but Gates says that he is even more optimistic that his organization will succeed than he was when he started the project.

Climate change challenging because of latency: Gates

He also sees climate change as one of the major challenges facing the world, though he doesn’t “put it above everything.”

“One of the reasons it’s hard is that by the time we see that climate change is really bad, your ability to fix it is extremely limited. Like with viruses, the problem is latency,” explains Gates.

Gates is personally backing nuclear energy as one possible low-carbon solution to growing energy needs, but he also argues that we should be investing in geo-engineering research and other ways to generate carbon-free energy. Even on seemingly intractable problems like world poverty, Gates believes that we can make far more progress than people realize. He has written in the past that he expects there to be few if any very poor countries by 2035, a statement he stands by in the interview.

America’s best days aren’t behind it: Gates

And despite the problems and inefficiencies of government, he thinks the idea that the US is past its prime is “almost laughable.”

“America’s way better today than it’s ever been. Say you’re a woman in America, would you go back 50 years? Say you’re gay in America, would you go back 50 years? Say you’re sick in America, do you want to go back 50 years?” asks Gates. “I mean, who are we kidding?”