Very white clouds result when water is suspended in the atmosphere as drops less than a millionth of a meter in diameter. These clouds reflect a large amount of sunlight back into space. We know how to artificially create such clouds with a water sprayer. A cloud produced in this way dissipates in less than a week as the drops evaporate into a gaseous form. Canada should install a number of these sprayers in the North to assess the benefits of this approach. If a cooling effect can be demonstrated it will give us more time to convert our energy culture from dirty carbon to clean fission. If the experiment does not work it won't do any harm either, being both inexpensive and of short duration.
These clouds makers will need a reliable power source - a small nuclear battery would be ideal. They could be placed near isolated Norther communities, thereby providing employment and something for Northern people to do to fight global heating. Being close to a town would offer other advantages such as the provision of electricity for the town. This would eliminate the dirty diesel technology presently used.
The time to act is right now.