Bitcoin mining has a hard-coded limit in the cryptocurrency protocol. This limit is 21 million bitcoins, and the current forecast is that the last Bitcoin will be mined around the year 2140. When this happens, the system will continue to work, but with some significant differences:
1. End of Block Rewards
Currently, miners receive a reward for mining blocks, which is made up of:
• Block reward: A fixed number of bitcoins, which is halved approximately every four years (an event known as halving).
• Transaction fees: Paid by users to include their transactions in the block.
When the last Bitcoin is mined, miners will no longer receive the block reward, only transaction fees.
2. Dependence on Transaction Fees
The economic incentive for miners will now be exclusively transaction fees. This could result in:
• Increased fees: So that miners maintain their interest in validating transactions.
• Reduction of miners: If fees are not sufficient, there may be a concentration of power in large miners or a decrease in network security.
3. Impact on Network Security
The security of the Bitcoin network is based on its decentralization and the amount of computing power dedicated to mining. If mining becomes less profitable, there could be:
• Fewer miners, increasing the risk of attacks (such as the 51% attack).
• Pressure for changes in the protocol or complementary systems.
4. Continuous Functional Network
Even without new bitcoins being issued, Bitcoin can still function as a financial system based on:
• Circulation of existing bitcoins.
• Use of transaction fees to incentivize block validation.
5. Possible Future Solutions
The Bitcoin community can develop alternatives, such as:
• Efficiency improvements to reduce dependence on miners.
• Changes to the protocol, although this is controversial and would require community consensus.
In short, when Bitcoin mining ends, the network will continue to function, but its viability will depend on how the transition to an economy based solely on transaction fees is managed.