Not in any order:

• Military / warfare

• Excessive HVAC use: heating/cooling unnecessarily large spaces (as opposed to zoned) and by more degrees than necessary

• Unnecessary and inefficient transportation. This includes most air travel, cruise ships, shitty urban planning, commutes for jobs that can be done remotely, large/inefficient automobiles.

• Cryptocurrencies and AI

• Consumer junk based on planned obsolence, lack of reliability, poor quality, and excessive packaging (often plastic)

• Food - increased per capita consumption of animal products and egregious amounts of food waste.

I don’t think any industry pollutes more per client served than the cruise ship industry.

The most impactful things you can do for the environment is to push your representatives to pass regulations. The USA is absurdly unregulated at the federal level.

Advertising.

Cause it’s driving over-consumption, by flooding people brains with shit ideas, turning them into idiots in the process.

In the US it’s roughly a tie between road transportation and energy generation (which lumps together both heat and electricity).

(Source: University of Michigan https://css.umich.edu/publications/factsheets/sustainability-indicators/carbon-footprint-factsheet)

The global breakdown is similar: https://www.wri.org/insights/4-charts-explain-greenhouse-gas-emissions-countries-and-sectors

The solutions? Build mass transit, live in temperate climates, buy less stuff, …? Honestly, I don’t think we’re not going to fix the problem with simple, local improvements (though by all means do what you can). There are global demographic forces to contend with. A century ago there were 2 billion people on earth. Now there are >8 billion, and in my lifetime we will surpass 9 billion. Many of those people are climbing out of poverty, and they want cars and air conditioners and all the other energy-intensive things that rich countries have enjoyed for a century. IMO we’re going to need massive technological changes (like powering much of the world with nuclear very soon) in concert with a major population reduction and/or major changes to how people expect to live.

Going vegan was the easiest for me. The Co2 impact is massive!

#1 Making more humans #2 Making less humans

There are numbers for these, you know. Biggest sources of carbon emissions are (1) burning fossil fuels and (2) land use change (converting natural ecosystems such as forests, grasslands and wetlands - to plantations, farmlands and concrete).

Most beneficial activity is <redacted>.

• Energy demand to power heavy industry that we all use (steel, aluminum, chemicals, fertilizers)
• • I don’t see these going away, so it’d be best to make their processes greener by repurposing the carbon into ag products, then institute a viable carbon tax and offset the rest of their footprint
• Use of concrete in construction
• • some promising technologies coming that crystallize the carbon and use it to self heal the concrete, carbon tax and offset the rest
• Shipping
• • bring manufacturing closer to consumers, global environmental manufacturing and shipping standards, improve right to repair laws
• Transportation
• • upgrade public transportation options where it makes economic sense to do so, make our cities and towns more people friendly instead of car friendly, raise the gas tax to fund these efforts. Reduce the amount of detached single family housing stock and encourage multi-family stock, particularly in cities.
• Heating and cooling
• • incentivize heat pumps, add taxes to heating fuels and fossil energy plants to fund it. Start a major campaign to educate people to keep temperatures around 68 (winter) to 76 degrees (summer). And encourage use of ceiling fans.

Honestly, capitalism.

The whole damn consume consume consume mindset. The idea that things are discarded instead of being repaired or properly recycled.

The excess production of useless shit that nobody would need or want without the manipulation of advertising convincing us otherwise. Cell phones and such are nice, don’t get me wrong, but do we need thousands of factories around the world churning out cargo ships full of cheap plastic junk that’s designed to fail? No. It only exists because it makes some rich people even richer, and it’s burning our planet down. If all that productive capacity was bent to the purpose of meeting peoples’ actual needs/reasonable wants it would be a different matter.

Bad

• Voting for reactionary or fossil industry-backed parties and candidates
• participating in local initiatives with climate action delay campaigns (eg “wind farm too loud”, “PV lowers property prices”, “bike lanes decrease spending”)
• keeping an internal combustion engine car,
• keeping a fossil fueled heating/cooling system
• paying for fossil fueled electricity plans
• building with concrete
• eating an omnivore diet with high waste lifestyle

Good

• Bicycling
• avoiding transportation
• using public transit when necessary
• decreasing load on electric grid
• using self-made energy (ie PV, communal wind) at the right time (ie washing clothes on solar peak)
• building with timber
• eating a plant-based diet with low waste lifestyle
• understanding LCAs of various materials and things
• increasing participation in circular economy (recycling, waste separation, repair shops, 2nd hand/gift economy)
• listening to actual science

Most beneficial thing is to choose a more minimalist lifestyle. Buy only if you need it, use only if you must and discard only if you absolutely have to. These principles can be applied to pretty much everything, from eating at a restaurant to buying clothes to using technology.

For typical middle-class people (like the ones probably reading this), usually the single worst thing they do is flying. It’s the only way to blow your personal carbon budget for the whole year in just a few hours.

That’s at the individual level.