Heat waves are hitting the globe from north to south, with the Arctic, parts of Australia and the central United States sweating record warmth in recent days.

The Arctic is in the midst of another hot spell, with temperatures soaring far above average for the third time this winter. The heat comes after yet another record-breaking month for low levels of sea ice at the North Pole, part of a dramatic and troubling warming trend that scientists have reported over the past few months.

In Oklahoma and Texas, temperatures reached into the 90s over the weekend. Mangum, Okla. broke a daily record when the thermometer hit 99 degrees on Saturday.Last week, Oklahoma Gov. Mary Fallin issued an emergency burn ban in response to the extreme weather, but a grass fire broke out anyway in Oklahoma City, prompting authorities to ask some residents to leave their homes.

Parts of southeastern Australia are also in the midst of an extreme heat wave, with temperatures topping 115 degrees on Saturday west of Sydney. The heat has helped fuel dozens of bush fires that are forcing evacuations. Authorities have said the fire conditions are as bad as they have seen.

For climate scientists, the relative warmth in the Arctic is arguably the most troubling. Temperatures in the far north of the planet have risen more than 20 degrees above normal on average in the past week, according to data from the Danish Meteorological Institute.

Last week, the National Snow and Ice Data Center announced that the polar ice cap in January stood at a record low for the 38 years it has collected satellite data. Compared to a year earlier, which set the previous record for the smallest January ice cap, the North Pole had lost a Wyoming-sized area of ice.

"I've been looking at Arctic weather and climate for 35 years and I've never seen anything like the warming conditions we've been seeing this winter," said Mark Serreze, the center's director.

Some scientists believe that climate change is exacerbating weather patterns that allow storms to bring warm air north. The melting ice cap may be playing an important role, scientists say. Patches of open ocean act like reservoirs of heat, pushing the warmth farther north. Water also absorbs far more heat than ice, creating a warming feedback loop.

In December, NOAA released its annual Arctic Report Card, which warned that if the extreme warming of recent years continues, the region could experience a climatic shift. The Arctic is warming at twice the global average, and mean temperatures over land have risen 3.5 degrees Celsius since the beginning of the 20th century.

The dramatic warming has prompted seemingly outlandish proposals from some scientists. Last month, researchers published an article that envisioned an array of wind-powered pumps that would bring seawater from below up onto the ice surface, where it would freeze and thicken the ice cap. An extra several feet of ice, the scientists say, would help the polar cap withstand the warmer temperatures that have been shrinking it to record levels. The authors also put a price tag on their proposal: $500 billion per year.