The benefit might not be immediately evident. In fact if we fix things it may never be evident. The problem with being environmentally sound is the same as managing a good department or company.

Nobody sees the need for the hard work while things are good. They want to increase profits and improve bottom lines by cutting costs.

In a company, this may ruin them in 2-5 years time. The cause and effect is easy to observe. The board gets rid of competent but expensive management or executives disrupt expensive procedures, then the company goes out of business. Maybe they all get sued because a change they made caused horrible, foreseeable consequences that they ignored to make more money.

The problem with the earth is its a system we can influence but our inputs are on a tiny tiny scale. This applies with both directions. Climate disruption and cleanup, but you need to remember that entropy makes cleanup orders of magnitude harder. Imagine you were a tennis ball company changing the composition of your tennis balls to save money, but you had 3 years worth of inventory. You wouldn't see the effect for 3 years. By that time you might not even remember the production change and wouldn't know that was why your tennis balls were exploding. Your company is ruined. The cost-benefit is clear. Don't make changes without testing their effects.

Now scale that up billions of times and imagine you had 100 years of inventory and you aren't allowed to alter the order that things were shipped. You also couldn't recall any potentially dangerous tennis balls once they were in the inventory.

It would take 100 years to observe the effects of a change. So if your worried that your grandchildren would be ruined you might extensively test before making changes.. however if you only cared about yourself and your bottom line then you might not do those things.

This uncertainty leaves lots of wiggle room for corporations more concerned with the bottom line. They point and say "see, the scientists don't have data showing what we're doing causes climate change". And they might be right.

I think small scale testing could be used to show the bad effects though. We can model the initial system input and ask questions like "does bunker fuel kill sea life in this small scale". What we can't model is the "cleanup" where we ask "if we stop using bunker fuel how long does it take for the system to recover?" There are just too many inputs and variables to model it currently.