Consider a global warming situation in which Earth’s temperature increases 2 ◦C over the next century. Further assume that the temperature increase is the same everywhere. Taking the average temperature gradient between the equator and the North Pole as 30 ◦C, and assuming that the boreal forest-tundra tree-line boundary is currently at a latitude of 60◦ North, determine how fast the tree line must move north in order to remain at the same temperature isotherm. Express your answer in m/day and m/year. Given that the boreal forest is an important global converter of carbon dioxide to oxygen, what are the implications and challenges of global warming on the boreal forest? Would your answer change if the global warming temperature increase was 0.5 ◦C or 4 ◦C?