@b6hydra 6 years of smoking cigerettes, 1 pack a day, would be equivelant in CO2 emissions to an iPhone 8's production and use over its lifetime. That doesnt account for other environmental impact of cigarettes such as the land use or the burden ont he medical system, So overall I'd say they are likely somewhat comparable in terms of impact, cigerettes may even be worse.
Source for iPhone is no longer up (404) but cited the iphones carbon footprint for production and lifetime use at 68 kg.Source used to be here:
https://glyde.com/blog/2019/08/25/why-choose-used-smartphones/
Carbon footprint is 1.39 per cigarette according to this source:
https://palebluedot.llc/carbon-copy/2015/10/14/the-carbon-footprint-of-cigarettes
@b6hydra The broken link I mentioned above can still be found in the internet archive so you can still read it thankfully.
https://web.archive.org/web/20200809172707/https://glyde.com/blog/2019/08/25/why-choose-used-smartphones/