My Honda Beat has been with me for almost 30 years now. I think I would continue to go with her for as long as possible.
  However, now is the time for decarbonization, and that has become a problem for old car enthusiasts.
　Recently, the technology of converting historic cars into EVs has advanced, but I think there are many people who still love the sound and vibration of the internal combastion engines.
　To address this dilemma, I have devised a method to achieve carbon neutrality much easier than EV conversion and without any modifications to the vehicle itself, and immediately put it into practice. The key to enable it was blockchain technology.

  The first thing to do is to calculate your car's CO2 emissions.
  CO2 emissions are theoretically directly proportional to the amount of gasoline burned, so it is relatively easy to calculate.
  There are so many detailed explanations on the web, so please search by yourself if you are interested.

  In my case, I have been using a smartphone app to keep track of my refueling, so I can find out that I have generated 1.48 tons of CO2 emissions in 2022, by consuming 628 liters of gasoline, which is hard for me to imagine, though.

  Once you know the amount of emissions, the next step is to offset the emissions by obtaining the same amount of "carbon credits".
  Carbon credits are generated by projects that absorb or reduce carbon dioxide, such as forest conservation and solar power plants.
　Methods for calculating and objectively certifying the amount of carbon credits generated are still under development, and it is said that there are some unreliable ones out there. My emission credits, discussed below, are backed by the methods set forth by Verra and the Gold Standard.

  Trading of carbon credits has begun on a pilot basis, but it seems that most of them are mainly for companies, and there is no service available for individuals at this moment (as of March 2023).

　Therefore, I chose to use Web3.
　KlimaDAO, a DAO (Decentralized Autonomous Organization) established in the fall of 2021, issues KLIMA, a virtual currency linked to scientifically backed carbon credits (digital carbon). By acquiring KLIMA and then using it to retire 1.48 tons of CO2 from the blockchain, my Honda Beat can be considered to be carbon neutral in 2022.

  Using this method, even on a personal level, you can voluntarily offset the CO2 emissions from not only historic cars but also, say, your home utilities and air travels on vacation, only if you can estimate the amount of CO2 emissions.
　In fact, since it is not possible to trade decimal points, I rounded up the number to offset 2 tons. Let's assume that I offset more to cover engine oil, tire wear, and other factors that are difficult to calculate.
　Well, it may be no more than self-satisfaction, but I am pleased to think that my car may have become the very first Honda Beat in the world to achieve carbon neutrality.

*There is a lot of information on the Internet about how to acquire crypto assets, so please do your own research if you are interested, of course at your own risk.