Two clashing climatic behemoths, one natural and one with human fingerprints, will square off this summer to determine how quiet or chaotic the Atlantic hurricane season will be.

An El Nino is brewing and the natural weather event dramatically dampens hurricane activity. But at the same time record ocean heat is bubbling up in the Atlantic, partly stoked by human-caused climate change from the burning of coal, oil and gas, and it provides boosts of fuel for storms.

Many forecasters aren't sure which weather titan will prevail because the scenario hasn't happened before on this scale. Most of t...