The tumbleweed dispersal strategies are unusual among plants; most species disperse their seeds by other mechanisms. Many tumbleweeds (though by no means all) are ruderal species, opportunistic agricultural weeds. Tumbleweeds have been recorded in the following plant families:
The most obvious is temperature. If the air temperature is above 32Â°F snow and ice will start to melt, at or below 32Â° and it will remain frozen. Think about a popsicleâ¦ inside the freezer it stays frozen, outside it starts to melt. The amount of sunshine plays a big factor.
In 2007, the year that Arctic ice cover set a new summertime minimum, 350 km cubed of ice was lost. Assuming this extreme rate continues, Greenland will be fully melted in 7400 years. Of course, ice melt rates are non-linear, and so this rate could increase considerably as temperatures rise.