>No one wants to pay the cost of tackling this problem.

No one can afford to. The most practical (wildly impractical and at present completely impossible) known method would be something akin to what YC proposes on http://carbon.ycombinator.com/desert-flooding/

They want to create 'pools' in the Sahara. Incredible amounts of desalination and pump the water into these pools to grow algae and then store the algae under anoxic conditions to effectively sequester the carbon. Problems with this:

- The cost simply to construct the pools, bring the desalination plants online, deploy pipes would be the single most expensive things humans have ever done, and may ever do.

- The power required to do this would exceed what humans already produce

- The amount of brine created would kill all life in coastal waters, we area already seeing this in the coastal waters of areas that currently heavily use desalination to provide freshwater to their populations. This would be on a scale several orders of magnitude larger.

- The amount of mining that would need to be done to provide the algae with what they need to grow beyond sunlight and atmospheric carbon

- The problem of actually sequestering thousands of gigatons of desiccated algae. Especially for the decades to centuries that would be required.

- The massive change in global weather patterns that could likely be catastrophic, that much evaporation over such a wide area would absolutely change weather patterns globally and would be extremely difficult to even remotely accurately model.

- Doing this in the Sahara would negatively impact the Amazon, the Sahara heavily fertilizes the Amazon as winds carry fine particles from the sand across the ocean. [1]

- The amount of clay, concrete, etc to create these 1 square kilometer reservoirs would alone likely make the project unworkable at the scale needed

- The cost of upkeep at the desalination plants, salt water is extremely corrosive, would cost unimaginable amounts of money. Maintaining pipes leading out to the reservoirs would similarly be extremely expensive.

- Running all of this pipe, in a desert you are suddenly introducing obscene amounts of humidity too via evaporation... you're probably going to generate some pretty incredible storms and it would not surprise me at all if you have regular failures/ruptures from lightning strikes on the pipes, the flash flooding (deserts can not handle even minimal amounts of rain well) would regularly cause massive damage to infrastructure as well

- Etc etc.

Sadly, the only realistic solution to the scenario is a fleet of alien ships showing up with exotic-to-us technology, gifting us clean power generation to meet our needs several times over and giving us some sort of widget to pull carbon straight out of the air and create carbon bricks out of it in exchange for IP rights to all of our tv shows and music for sale to the Galactic Hegemony.

The next most realistic solution would be to agree as an entire planet to safely shut down all fossil fuel processing operations and nuclear reactors, then EMP the entire planet and hope we can survive the next several decades of destabilizing weather while we learn how to be a pre-industrial revolution society again and wait a few centuries for the Earth to start to deal with the carbon on its own.

[1] https://www.nasa.gov/content/goddard/nasa-satellite-reveals-...