Solutions to Global Warming
1. Population Reduction
Population reduction is the most sensible solution. The best way to burn fuel and reduce emissions is to have less people burning the fuel. Greenhouse gas emissions can be halved by halving the population without affecting lifestyle. An Earth with under 1 billion people might have slow enough growth, and enough space for plantlife to be sustainable in the long term. Reducing the population in this way would require concerted, but feasable, actions by governments.
2. Lifestyle Changes
The one most governments are plugging for is for people to use less carbon producing fuels and generally live while emitting less of the greenhouse gasses. This is doomed as long as the population continues to increase. According to Newsnight, meat as a food already contributes to the greenhouse effect more than all of the transport on Earth and the demand for meat will increase as the population does, as will the demand for transport. I remain sceptical about even the possibility that changing lifestyle can reverse global warming to any extent. Even a caveman produces carbon dioxide from his camp fire, and several billion cavemen would still damage the planet, even if only from mass food growth and consumption.
According to the book Why Don't Penguins Feet Freeze, If all of the inhabited concreted areas of Earth were painted white the reflectivity of the surface would increase by an amount capable of lowering the global temperature by one degree. The black oceans probably absorb far more heat than necessary. A white or silver coloured bateria that thrives on the surface of warm sea water would multiply, cool the Earth and, once the Earth is cooled, die off in the cold seas (assuming it didn't mutate enough to prefer cold seas).
4. Dust, Volcanoes and Nulcear War
Particulates in the atmosphere have a large effect on global temperature. One medium-large volcanic eruption can lower the average global temperature by one degree. A massive eruption can lower the temperature by ten degrees. It's perhaps ironic that the environmental laws that stopped the output of soot from factories in the 1970's might have inadvertantly created global warming because the soot was keeping us cool. One radical solution to global warming might be to remove those environmental controls and actually force factories, cars and aircraft to fill the air with smoke and dirt once more. Of course that would make the world unpleasant but that unpleasantness might encourage the factories to limit the amount they burn. A nuclear winter is an even more radical option to global warming, this need not involve war but a large attack upon any dusty area such as a desert.
5. Refrigeration and Robotics
Numerous gadgets might counteract either global warming or greenhouse gas emissions. Solar powered refrigerators could literally cool the planet. Huge machines could be used by governments to extract greenhouse gasses from the air and convert it back into solid carbon. Plantlife could be genetically engineered to extract carbon efficiently. Plants would have to be buried to trap the carbon, just as the plants that became coal were buried. All so-called carbon off-setting schemes really need to bury the plants they grow, yet amusingly none do allowing the plants to decay or become burned. Perhaps a farm animal can be invented that inhales carbon-dioxide and exhales oxygen, reversing the negative impact of the cow on climate.
Perhaps the most unexpected answer to global warming is not to do anything, and trust that the Earth will self-balance somehow. All of the coal and oil under the Earth was at one time plantlife on the surface of the Earth and all of the carbon in it was in the air. Things balanced out over time. I doubt whether mankind can tolerate the overcrowding, lack of resources and general lack of comfort of living in a "warmed-out" Earth, but I pessimistically suspect that this is what will happen anyway. The stability of past is not a guide to the future though, the sun in particular has been growing hotter with each passing million years. In a worst case all life could end if one part of the ocean reached 100 degrees. The sea would boil, liberating steam (steam is a powerful greenhouse gas), and setting Earth on a runaway trip towards a lifeless Venus-like world.