"..seems like..." is not the correct operative word. We KNOW that the last time the planet was warmer than it is now, it was a period of great beneficence to most kinds of life (especially human). The "Medieval Optimum" period WITHIN RECORDED HISTORY was warmer than now, and the historical and archealogical record all indicate that it was a "boom" period for humanity.
The "global warmers" are just looking for another lever to overturn our liberties and institute more CONTROLS over our lives.