If most countries worldwide were to ban Bitcoin mining, would the remaining hash power be sufficient to secure the network? What impact would this have on Bitcoin's decentralization?

Is the Remaining Hash Rate Sufficient to Ensure Network Security?

Bitcoin network security heavily relies on global hash rate. A higher hash rate makes it more difficult for attackers to launch 51% attacks (such as double-spending), as they would need to control over 50% of the computational power. If most countries ban Bitcoin mining, the global hash rate would plummet (e.g., after China's 2021 mining ban, hash rate dropped by approximately 50%). In the short term, the remaining hash rate may be insufficient to maintain the original security level, increasing network vulnerability and elevating attack risks.

However, miners may relocate to mining-friendly jurisdictions (e.g., the U.S., Canada, or Kazakhstan), allowing hash rate to gradually recover within months. Historical cases demonstrate the network's resilience, with no major attacks occurring. Long-term, the remaining hash rate could stabilize through adjustments, though the transition period carries heightened security risks. Conclusion: Likely insufficient short-term, but recovery is possible long-term, provided miners successfully relocate.

How Does This Impact Decentralization?

Decentralization is Bitcoin's core principle, designed to prevent single-entity control. If most countries ban mining, miners would concentrate in few permissible regions (e.g., jurisdictions with lenient regulations), leading to mining centralization. This would increase market share for a few mining pools or entities, heighten 51% attack risks, and weaken censorship resistance and network distribution.

Conversely, bans might force miners toward geographically dispersed setups (e.g., leveraging renewable energy or small-scale operations) to mitigate regulatory risks, partially enhancing decentralization. In practice, however, economies of scale often prevail, strengthening centralization trends. Conclusion: Overall weakens decentralization, increases centralization risks, and potentially undermines Bitcoin's censorship resistance and trust foundation.