How about choosing destinations, hotels, and dive operators that strive to be eco-friendly or base their business around that? Vote with your dollars and support properly-run ecotourism. Much more effective than not using straws.
Check out dive destinations that are closer to home.
Find out if there are local stewardship organizations that protect the places you're diving (local or travel) and donate to them.
Carbon offsets for air travel aren't that expensive for one trip, I use them sometimes. If you personally don't like or trust the carbon offset businesses you can make an equivalent donation to a climate organization of your choice when you travel.
Buy dive gear made in first-world countries that have actual labor and pollution standards, even if that gear is more expensive because of it. Seems asinine to save $50 on a regulator if the waste chemicals from metal plating it are dumped directly into some river in china that flows into the ocean where you will be diving.
Sorry bro, no way you can paint dropping literally tons of C02 per person as environmentally concerned. Not to mention the effects of the metals mined to make those vehicles, the resources used to make the airports etc. It would literally be more environmentally responsible if possible and long enough bridges existed if every single passenger drove themselves there one person per car instead of using commercial air travel. Trying to spin it like we're some kind of environmental superhero for not using straws while dumping tons of poison into the atmosphere, the very water we're going to dive and the land we live on is just sad.
This is partially true. But also somewhat defeatist. It IS possible and good to make better choices, even if small. I agree that that there are bigger (though more difficult) issues to address than straws. I'm not sure if driving over huge bridges to the Caribbean really would be better. It would be interesting to math it out. Concerned air travelers can offset their carbon impact by supporting environmental projects directly, or buying carbon offsets that do. That is a real way to make flying okay.
Also, the link in your signature has some serious anti-environment crock that makes your whole post seem disingenuous . Overfishing is a huge, immediate, and direct threat to the places we love to dive. The organization you promote is against fishing vessel monitoring and marine protected areas. Like WHAT?