What is the main cause of global warming

It is caused by increased concentrations of greenhouse gases in the atmosphere, this is driven by human activities including the burning of fossil fuels, and farming.

It is cuased by the ice melting... I think

the answer is crop rotation

tropical storm katrina, and it made landfall between miami and fort lauder-dale, florida, as a category 1 hurricane (a storm that, on the saffir-simpson scale, exhibits winds in the range of 74–95 miles per hour [119–154 km per hour]). sustained winds of 70 miles per hour (115 km per hour) lashed the florida peninsula, and rainfall totals of 5 inches (13 cm) were reported in some areas. the storm spent less than eight hours over land. it quickly intensified when it reached the warm waters of the gulf of mexico.

this should answer you're question