Specifically on an European diet(~1.5-2g CO2/kcal) a cyclist is responsible for ~27g CO2/km, which is not negligible and puts cycling on par with public transport.
I don't believe cycling to be a solution here. It's said that 25% of trips in the Netherlands are currently done by bike, but what is left out is that, according to this study(2012):
https://www.tandfonline.com/doi/abs/10.1080/01441647.2013.80...
50% of trips are still done by car.
Looking at distance traveled it's 75% cars and 8% bicycles.
That's after decades of changes in infrastructure to accommodate cyclists.