Another challenge to food production and land and water conservation is the rising interest in vegetable - based biofuels, which requires the use of hundreds
of millions of square kilometers of farmland and cleared rainforests.
The arctic ocean may be millions of square kilometer [1.4 million] but have this effect why isn't 10,000 square kilometer of open ocean not enough to have regional effect.
The meters thick ice
covering millions of square kilometers has enough thermal inertia to shrug off warm weather (at least it has for hundreds of thousands of years), but not resist a warming climate.