The point is not that humans have "no effect" on climate. Of course we have an effect. But the effect is so small that it makes no sense to worry about it. It's like thinking that you can save money by taking a shower three times a week instead of five times a week. You're not going to save much money that way. You'd be better off moving to a place with cheaper rent, getting roommates, or getting more hours at your job, higher pay, etc.

In the same way, if the Earth is warming, you need air conditioning. If storms are becoming more numerous, you need better early warning systems and better means of transportation to get out of places hit by a storm. You need to invest in technologies that protect you from adverse climate.

The alternative is to reduce energy consumption, which will make you more vulnerable to the climate. After all, air conditioners burn energy. And burning energy produces CO2. So, ironically, being concerned about global warming will make the Earth more, not less, inhospitable to humans.

At the same time, reducing energy consumption will not actually stop the Earth from warming. In order to stop the Earth from warming by reducing CO2 emissions, we would have to reduce the amount of volcanoes erupting and respiration by humans and animals. But this is impossible. We don't have that kind of control over nature.

So the issue is not that the burning of fossil fuels has no effect on climate. It's that the emphasis on fossil fuels is misplaced when there are so many other things that emit CO2. And, fundamentally, it's a flawed belief to think that human beings can control the climate. We're just not powerful enough to do that.