to a month... for ling term traveling 3 months seems to be when people hit the brick wall or find a new lease of life and want to continue... for me anything under 6 months is a short trip haha.... (foreverroamingtheworld.com)
The United States did not have an official K9 program ling time. (snowyswan.com)
In addition, non-greenhouse effects such as ling term ocean currents and Sunspot / cloud effects are not reasonably included in the arguments. (scienceofdoom.com)