There is only one way forward: The external costs of the economic activity must be internalised. There are two solutions to achieve that outcome. Taxation or handing out a limited number of emission permits that are traded with a market price.
Everything else is a waste of time/money as there are people on this planet who would do everything to make a profit. Therefore the only solution is to make the profit achieved by really dirty operations go away.
Further, CO2 emission and climate change is not the biggest problem of the humanity. Loss of biodiversity is maybe even worse as it is never ever reversible.
So true. Even if, as OP posted, you did something like cover the Great Lakes in green algae, if you fail to force everyone to internalize negative externalities, it would just be a matter of time before any gains were destroyed again.
Build a starlink-style satellite fleet in a ring around the earth, facing the sun head on.
Each satellite is basically a circular, large, thin-sheet mirror that pops open and unfolds from a coiled, folded, initially small packed size.
The outer edge is a conductor that can carry current and induce a magnetic field that is used to rotate it against the earth's magnetic field.
These can be used to focus sunlight on the pacific to generate cloud cover to tweak the earth's albedo at first.
Later when there are more, say about enough to filter 2% of incoming solar radiation, they can be used for fine-grained tweaking to control incident solar radiation using the controlled shadow they cast combined with the occasional reflective heating of spots to tweak wind flows and large body of water temperatures.
Coupled with climate modelling we use these to initiate a climate control programme which along with CO2 sequestration and some glacier geoengineering gives us our own climate as a garden.
PS: Maybe a lot of them focused on a small area could melt rock, in which case one could maybe carve channels for water to tweak water availability in large inland areas to allow modification of moisture/rainfall patterns.
Fund and establish the Green party in the US (and in other countries if some cash is left after paying all the lawyers)
Support those efforts making ecocide an international crime.
Strengthen the Den Hague court.
Create an international task force to arrest war criminals anywhere on earth.
Invent mangrove farms (they must yield _some_ economic value?)
Take all good people of influence on a boat trip to support your cause.
A few potential goal definitions which can be wildly contradictory: - maximise the probability for Earth to remain habitable until cosmic conditions (the Sun's decline) dictate otherwise, for humans, - ibid, but for for as many species as possible, - identify and implement the most optimal way to coexist as a species toaximised learning and knowledge advancement, - etc.
It feels like long-term, multi-national, consequential fundamental research could be undertaken on an interesting scale with such a budget. This in turn could highlight scenarii of different ways forward to inform and influence policy-making. It may be one of the best ways to spend it.
Plant forests after buying up land. Make robots that clean up the plastic in the ocean. Make hydro plants to replace coal burning plants. You still don't have enough to do this for the whole world.
Except the only people included in the snap are: authoritarian regimes, militias, leaders as well as all politicians, diplomats, judges, lawyers, corporate boards, oligarchs, anyone worth more than a billion, hummer / gas guzzler drivers etc...also I'd cause a world-wide emt that would disable electric grids for awhile...
Every country would basically run elections to decide if they want to keep their current constitution, start from scratch, or join a bigger union globally or regionally or split into smaller city-states... then they draft new legal frameworks/constitutions etc... if nothing changes Thanos threatens to return every decade and rinse/repeat.
Kind of like Sodom and Gomorrah, I guess...though i'm agnostic.
I think finding non-existing infinity stones though might cost > $100 billion lol.
Alternately as someone else said...buy politicians lol.. <-- that is probably the most effective way to push an agenda/make change -sadly.
The below all are easier machine learning problems than self-driving cars, yet no big tech companies or national initiatives are focused on aggressively applying machine learning to them.
Likely a couple of billion dollars, a year, and a 100 people lab would 'solve' each specific problem.
1. Robot that cooks meals, and clean the dishes afterwards. That saves billions of hours daily.
2. Robotic self-cleaning toilets. Saves another billion hours daily.
3. Robots that can dig up dirt and build a house from that dirt.
4. An app that can teach anyone anything like a teacher would - literally - a talking avatar and cameras and voice output and machine learning powered dialogue.
5. Home manufacturing 'box' that can make 95% of anything that anyone typically wants (some arrangment of 3d printer/laser cutters/pcb placement/wood router machines etc, that can take plastics/wood/metal/electronic components and output a gadget/furniture etc)
The above 5 give the equivalent of a 'basic income' for everyone (if distributed to everyone, and assuming the finished gadget is about the size and complexity of an automobile).
Then the inputs/ouputs problem of energy/raw materials/waste needs to be provided. Disregarding scientific advances like fusion power etc (which require more than 100 billion maybe, or not possible), a drone distrubution platform for getting the energy / matter (input/waste) handled. To do this (as above, 100 people, a year, 1 billion dollars)
6. p2p aerial surveillance system for air traffic managment of millins of drones. Basically, a sky pointing camera gadget that analyzes and broadcasts what it sees and process. Millions/billions of these camera gadgets airdropped every few 100 meters .
7. a drone that can carry 100 kilos and drop ship materails/waste p2p using the p2p air traffic control. The drones are battery operated with range a coupel of kilometers.
8. a drone that can mid-air 'refuel' the above drones. Basically a flying battery that recharges that larger cargo drones.
Summary - 'gadgetize' every problem (it becomes a self contained mechano-electrical desktop/fridge size thing that a team of 100 people can rapidly iterate on) and throw machine learning at it at heavily as possible. Seek to eliminate human labour as fast as possible.
I would instead recognize that I am no expert in how to solve this crisis, and would probably do some unforseen harm if I would just start doing things that I personally believed were beneficial.
Instead I would put my truat in actual experta and acedemics and start pouring money into the starved research sector, as well as NGO's and other entities that produce science backed policy suggestions for governments all over the world.
We need to get everyone, and their policies, on the climate's side if we are to stand any chance of reverting the damage we have and continue to do.
I am accepting that there are some things that x amount of money will not fix and simply targeting a problem where x amount of money and the right leadership can develop a model for ending homelessness that can be easily replicated elsewhere.
The answer would not be simple but employing lots of useless people, in the name of charity (as is the current 'solution') is one model I wouldn't be implementing.
So I would fund alternative food startups - even by subsidizing existing products, to ramp up scale, and thus attract technology investments and lower costs, in exactly the same way as has happened with govt. support for solar panels
This is the lazy way to answer the question, but when electric self driving cars get practical and scaled (some time in the next 10 years), CO2 emissions will significantly decrease.
:)