by Kerry SHERIDAN Agnce France Presse TAMPA, United States (AFP) — An Arctic-like deep freeze gripping much of the United States with double-digit subzero temperatures is the coldest of its kind in two decades, but is it linked to climate change? Experts say it could be, but whether global warming plays a role in this particular extreme weather phenomenon is still up for debate. Here’s why: What is a polar vortex? “It is a mass […]