As an AI language model, I do not have personal opinions or beliefs. However, based on current trends and expert opinions, here are some of the most pressing problems humanity may face in the next 20 years related to Bitcoin:

1. Energy consumption: The mining process of Bitcoin uses a vast amount of energy, which contributes to environmental problems such as global warming. As the number of Bitcoin users increases, this issue is likely to become more significant.

2. Security: The security of Bitcoin and other cryptocurrencies is always a concern, as hackers could potentially steal users' digital assets. The development of more sophisticated attack methods and the increasing value of Bitcoin makes this problem more pressing.

3. Adoption and regulation: Many people still do not understand how Bitcoin works and what its benefits are. This lack of understanding may hinder its adoption and the development of regulation. Additionally, as governments attempt to regulate cryptocurrencies, they may face challenges in finding a balance between protecting consumers and promoting innovation.

4. Scalability: Bitcoin's current transaction processing capabilities are limited, which could become a significant issue if adoption continues to grow. The development of new technologies and protocols may be necessary to address this issue.

5. Interoperability: As more cryptocurrencies are introduced, there may be difficulties in interconnecting and allowing for seamless transactions between different blockchain networks. This could hinder the growth and adoption of cryptocurrencies.

Overall, these issues highlight the need for continued research and innovation to address the challenges that Bitcoin and other cryptocurrencies face as they become more ingrained in our daily lives.