Those are all awesome ideas, but I don't think they are realistic.

More CO2, more trees.

The amount of CO2, or rather the amount of carbon and oxygen, is a given. There is never any more nor any less of it. It only depends whether you have it bound (e.g. inside a plant) or floating free. The problem with more CO2 is not that it's harmful in any significant way. The problem is that it very minutely increases temperature and thus very radically changes the climate and climate zones.

Those trees couldn't care less whether there's a little more or less CO2, but we do because we are adapted to some particular climate, and some particular cycle, as are the highly specialized animals and plants that we cultivate for food. The highly specialized houses that we live in are made for exactly one particular climate, etc etc. The tiniest change will be extremely painful to say the least. Trees will always grow, even after we're gone.

How about limiting family size worldwide to 2 kids per family?

In most European countries, governments would be very happy if families even had 2 kids each. China does that "2 kids max" thingie since pretty much forever, and to no avail. Africa... well... good luck with your idea.

claiming the oceans to build city islands Solution: this is still urban expansion, but instead of expanding in to the forest they are expanding in to the seas, so same solution as above

This is particularly awesome because
a) you need huge amounts of sand (no, the huge amounts of sand that the UAE have are not suitable for that due to its microstructure)
b) that sand is stolen by sand pirates
c) as you build artificial isles in point A, isles disappear in point B
d) disappearing isles mean territories change (go ask Vietnam how intelligent it was to sell billions of tons of sand to Singapore)
e) ocean rises a few centimeters, and everything you built up expensing a lot of energy is... gone

How about removing and disbanding all Antarctica and Arctic research bases

What you call "research bases" are in reality outposts. They exist so the nations that hold them can plant their flag onto uninhabited ground and claim the natural resources. No outpost, no claim on the unexplored lands. Not going to happen.

Artificially cutting down of trees in many countries due to huge urban expansion rates.

What about cutting down trees to produce pellets because they are soooooooooo eco-friendly? You should rather kill all those fucking Greens that come up with bullshit ideas like cutting down 300 year old trees for burning, and call that "sustainable". I question how it can be sustainable to use something that nature produces in 300 years for fuel.

What about burning down several square kilometers of rain forest to no avail every day (as bad as it is to use trees for producing energy, they're not even doing that, they just burn the forest down so it's gone...). What about cutting down trees and selling them to China to make... toilet paper.

You are right in one thing: Trees need CO2. You are wrong in another: More humans do not heat up the planet (well, the cows we breed to feed them might thanks to the methane they produce... but then, humans don't need nearly as much meat to survive as we currently produce).

CO2 does... of course, the rise in CO2 omission is indirectly linked to the rising population, but ONLY because more humans nowadays means more cars, more planes, more houses with central heating, more need for electrical energy...

CO2 reduction alone will not steer the ship around, that is clear. But if you don't reduce the amount of CO2 emissions, everything else you do kinda goes to waste. You don't need to cut down less trees as long as CO2 emission is still on the rise... you need to plant additional trees. A lot of it. Question is, where, while forests disappear everywhere?

The ice on the poles is not melting because of some tiny bases stationed there, thats ridicolous... though the large scale resource scavenging going on there since some decades might actually have a detrimental influence and should be stopped. Stop using oil naoh, while there are still reserves worldwide should we need the oil in the future (and before all the bound CO2 is blown up into the atmosphere)!

Good luck with limiting family size. Not even China is able to hold that up well anymore. The one kid policy is gone, and AFAIK if you have the money you can have more than 2 kids today (just make sure to keep a low profile so your name doesn't pop up during their next anti corruption purges).

Filling up the sea with cities is not a good idea, even if technologically feasible... you know what is actually binding even more CO2 than trees? The algae and seaweed. How do they grow? With sunlight. And what blocks sunlight and thus kills those plants? Your shiny new floating cities!

Lets not get into the even more ridicolous idea of building artificial islands for your cities... samoth has said all there is to say to that idea.

CO2 emission reduction, as hard as it seems in todays industrialized society, is maybe the easiest way to limit climate change we have... it might be the only realistic way.

In a perfect, worldwide, fascist Misantropia Utopia you might be able to do more... you know, when you have a dictator that can tell people to stop breeding like animals, to stop trying to squeeze everything out of the few more or less untouched areas on earth still remaining, to stop breeding cattle and eating vegan instead, and replace having fun with thinking about the future of our kids (we no longer are allowed to have)....

In our own, imperfect, multinational and -ethnical world, we can only do what the common denominator allows us to do. And that is lowering CO2 emissions... because thanks to newer technology, they don't hurt nearly as much as no longer being able to eat meat every day, or having to limit your family plans, or not cutting down forests for nice shiny wooden trinkets and more space to breed cattle that fart out even more methan gas.

The important thing isn't whether it's benefiting "the planet" (as if that even has any real meaning), but whether it's benefiting us. For all we know, the climate could stabilize in 10 million years and kickoff a biodiversity renaissance in the world's oceans. Problem is, that doesn't really help us at all in a reasonable timespan.

Frankly, I'm not convinced we can solve the global warming problem by reducing emissions. We can't bring them down to zero, and nobody knows that sekret number that magically means that "nature" can make up the difference. If anything, I'm convinced the global warming crisis will only resolve itself when/if we as a civilization develop the technology for controlled planetary terraforming.

EDIT: and in line with Gian-Reto's post above, I agree that we can and should mitigate the problem with reducing CO2 emissions, but we need to accept that it's simply not possible to solve with that alone.

What about cutting down trees to produce pellets because they are soooooooooo eco-friendly? You should rather kill all those fucking Greens that come up with bullshit ideas like cutting down 300 year old trees for burning, and call that "sustainable". I question how it can be sustainable to use something that nature produces in 300 years for fuel.

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