Eat less or no meat probably. Enough people drive down meat demand would eventually lead to cattle reduction and less land for grazing.

Vote.

Eat your nearest billionaire.

Wear a condom.

There is nothing you can do to reduce your carbon footprint that comes even close to having no or fewer children.

You can get rid of your car, stop eating meat, recycle as much as you can and so on, but the impact of that together is a fraction of the reduction you can achieve by simply not creampieing your gf/wife.

You’ll also save a ton of money and you don’t have to deal with any annoying kids so it’s a win/win all around.

Anytime you have a chance to vote, take it, and vote for whatever option will be most likely to reduce the overall emissions. In most cases, this will probably mean voting for programs/parties etc that oppose conservatism.

Wear a condom.

Public transport and bikes to avoid overusage of cars. Many people seem to make a big deal out of this but to me it seems reasonably simple.

Please stop listening to corporate propaganda on this subject. You have absolutely no personal responsibility to solve this problem. The idea that you have to is an invention from business. A way to make it a personal responsibility and not something businesses have to solve.

100 companies/corporations are responsible for 71% of all greenhouse gas emissions. Unless the "simple changes" are "abolish capitalism and give these polluters the corporate death penalty" then there's jack shit you can do to have any appreciable impact beyond not having kids and convincing everyone you know to do the same. Because if the human race goes extinct there will be nobody left to pollute.

• Eat vegan, the more local and the less processed the better.

• Opt for cycling, walking, or public transit rather than owning and driving a car.

• Shop secondhand (thrift stores, FB Marketplace, Kijiji, yard sales) whenever possible, especially clothing and electronics.

• Re-examine your consumption habits, we probably don't need (nor really even want) like half the stuff we buy.

Honestly, I believe a big negative social reaction to yachting and private flights for the wealthy would have the most impact. You can't necessarily force people to not do things but you can create a negative backlash.

Vote for better policies and laws that force companies to be better as well.

Even if we improve ourselves as much as possible: We still need the products of big corps which only improve because of (1) laws or (2) when losing money.

"Ethical consumption" is fine, but have a very low impact: Most of environmental damage is related to corporations, not by population.

Information is key: To solve any problem, we need to understand it the best we can. So how climate change works? How human action is driving it? Who is responsible? And what are our options? Look for science communicators that reflect the scientific consensus, not the opinion of a small group.

Be aware of/with any "solutions" that is proposed by or also benefits big corporations and the billionaires that owns it. There is a lot of green-washing shit around.

Vote for politicians that have a solid green agenda. Votes matter, but in capitalism, it is not enough. The capitalist system is built to maximize profit over everything else, that's what will happen if there's nothing stopping it to happen. So political education and engagement makes difference.

Don't fly.

I agree with a lot of people that suggest voting and holding your representatives accountable and the mass pollutors responsible will be the most important part but I also think there's no reason not to lead by example in this situation. Reduce your carbon usage when you can by buying fewer consumer goods, eating less meat, avoiding single use products, and more frequently using public transportation, walking and cycling to get around.

Here are some of the things we are doing that to us, don't feel like sacrifices:

1. People say become vegan, but for me personally, that would feel too restricting, so my husband and I stopped eating mammals instead. We still eat chicken, turkey, fish (rarely) and seafood (also rarely).
2. Work remote if able
3. Grow a garden, even if all you can do is a windowsill herb garden. There are so many possibilities you can have. If you have a balcony, you can buy a greenstalk, where you can grow tomatoes, herbs, peppers, strawberries and all kinds of stuff. It doesn't take very much space, and can be very efficient. If you have a little bit of land available, you can have some raised beds or just grow in ground (I am growing with a no dig method for example). You can also put in perenial plants such as blueberries, elder berries, black berries, raspberries, honeyberries and so much more that is really not going to require much of your attention beyong the initial effort of putting it into the ground and then harvesting once the plants start producing.
4. Start sourcing your food locally. The best way of doing this is finding a local CSA (community supported agriculture). We are CSA members of a farm that's literally just a couple and their kids who grow 90% of their own food, and feed the local community too. The stuff you will get from CSA is not only locally grown, but it is the freshest, tastiest produce you will ever have in your life. Sometimes it even ends up saving you some coin, because you are not going through middlemen.
5. Learn cooking from scratch.
6. Don't have kids.

But at the end of the day, you have to remember that you are just one person. Unless corpos decide to make changes, likely nothing we do will truly matter... I do all of these things, because it makes me feel better. Gardening is therapeutic, and you get amazing food out of it. Plus it is a very valuable skill to have, especially given everything happening in the world.

Read anarchist philosophy

Eat vegan.

Go vegan. Continue protesting in a way that actually helps, striking together, showing where the power actually is.

If you can't ride a bicycle, go out of your way to make riding safer for others by never using an idiot brick behind the wheel, and driving safely. You are not important on the road. You are not an exception under any circumstances. You always need to park in a parking space. You never have a right to double park. Your special situation is a dilution of your own invention. Your delay or rush is your own incompetence and you are the only one to blame. Your 10 seconds or even your 5 minutes is not more important than someone's life. Back roads are not your secret, an alternative highway, or a racetrack. Drive like the airbag is really a dagger pointed directly at your chest because your car is just as deadly and just as dangerous to everyone else. Pedestrians, including cyclists always ALWAYS have the right of way. No matter how prejudice you are and how anger this makes you, you WILL lose in court, and likely everything you own, as hitting a pedestrian doesn't have the same limitations as hitting another vehicle; your liability insurance won't even remotely cover this issue. I was disabled while riding to work in 2014; by someone who double parked; then made a sudden u-turn directly into another car and nearly killed me with a broken neck and back. Stupid drivers should have lethal or at least life changing consequences. "Safe" cars create stupid drivers. There is no effective low bar for a drivers license. The number of times a person can take the test is infinite. There is no effective white and blue collar alternative public transit system in the USA outside of Manhattan. Buses are not remotely professionally viable, and trains like in SoCal have inflexible, sparse schedules that just don't work in the real world. I have tried them. There must be an efficient nearly point to point method of transit every 15 minutes 24/7-365 or you work for your transportation not for your job.