This is an excellent question! Global warming is occurring at a very fast rate; the average surface temperature of the earth has been increasing at a speed of about 2˚ Celsius per century for the past 30 or 40 years (Hansen et al., 2006). This may not seem like a lot, but it could have a huge impact on human civilizations. Human activity releases greenhouse gases, such as carbon dioxide and methane, that cause energy from the sun to be trapped in the atmosphere instead of reflecting back into space, and most scientists think that greenhouse gases are the leading cause of the global warming trend that is currently happening. An obvious way to protect ourselves from global warming then is to decrease the amount of greenhouse gases that we are putting into our atmosphere. Much of the greenhouse gas that goes into the atmosphere comes from fossil fuels like gas, oil, and coal that we burn to power our cars and airplanes, heat our homes, and generate electricity (we use fossils fuels for many other things as well). We can slow down how fast we put these gases into the atmosphere by using other sources of energy such as solar and wind power, that are known as clean energy sources. We have been starting to use solar and wind technologies more and more over the last few decades (California actually has the largest solar power system in the world), but we still rely on burning fossil fuels. We need to make an even greater effort at decreasing the rate of fossil fuel emissions to have the needed effect.

A more active approach for slowing down the buildup of greenhouse gases (especially carbon dioxide) in our atmosphere is to trap them in some sort of long-term storage. One possibility is to trap carbon dioxide in rocks. There are certain types of rock, particularly rocks that make up the ocean crust and upper mantle of the earth, that can react with carbon dioxide to form minerals such as calcite and magnesite (Matter & Kellemen, 2009). These minerals can act as long-term storehouses of carbon dioxide and keep it out of the atmosphere.

Global warming is already happening, and has been happening at a very fast rate for several decades. It is important to try to figure out ways to slow it down, but it's also important to learn to deal with its effects. A large proportion of people on earth live near the coast in areas that may be effected by sea-level rise and more intense storms. It's important to prepare cities near the coast for changes that will happen due to global warming. This might mean moving people away from the lowest parts of the cities that will be under water when sea level rises. It is important to predict (make educated guesses about) what will happen to civilizations in different parts of the world as the temperature continues to increase. We can then use these predictions to take actions to protect the people and the property in areas that might be most strongly effected.

References
Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D. W., & Medina-Elizade, M. (2006). Global temperature change. Proceedings of the National Academy of Sciences, 103(39), 14288-14293.
Matter, J. M., & Kelemen, P. B. (2009). Permanent storage of carbon dioxide in geological reservoirs by mineral carbonation. Nature Geoscience, 2(12), 837-841.

Short answer:
I think we will "protect" ourselves from global warming through a combination of (1) decreasing our CO₂ emissions (through increased energy efficiency, carbon capture and storage, and eventually shifting to alternative energy sources), (2) removing some of the excess CO₂ that we have already put into the atmosphere with technology like "artificial trees," and (3) adapting to the consequences of global warming.

Long answer:
The best way we can protect ourselves from global warming is by taking actions now to reduce the amount of CO₂ we are putting into the atmosphere. If we do not take strong actions, we will have to deal with the consequences of a 2-4°C increase in the global mean temperature by the end of the 21st century. These consequences include sea level rising 1-3 feet, increased hurricane intensity, an increase in droughts in many areas, and increased flooding in other areas. To some extent, we will probably have "protect" ourselves from these consequences by adapting to them, for example building desalination plants to deal with shortages of drinking water or building dikes to protect against rising sea level. Of course, it will be more difficult for developing nations that may lack the resources to adapt, and it will likely be devastating for many ecosystems.

Geoenginering projects that seek to reduce the amount of solar energy absorbed by the Earth are the riskiest of all, and therefore in my opinion, least likely to be used to protect us from global warming. These projects involve reflecting sunlight away from the Earth, and range from using pale-colored roofing and paving (white reflects radiation, black absorbs it), to reflective aerosol particles to the atmosphere, to put mirrors in space to reflect away some of the sun's energy. These projects would reduce the average temperature, but they would not do anything for other problems caused by high CO₂ levels, such as ocean acidification, and we don't really know what all the side effects would be.