"It's not to say climate change isn't happening. It's not to say jellyfish (population increase) is not happening," Haddock said. "But I think there are so many causes that would come before climate change that it doesn't seem that productive. It sounds to me like scary rhetoric to try to get funding, or to get people all excited about it."
Scientists will need at least a decade's more work before drawing any definitive conclusions about population numbers, Rob Condon, a marine scientist at Dauphin Island Sea Laboratory in Alabama who headed the cycle paper, told LiveScience in a previous interview.
Haddock encourages anyone interested in jellyfish to submit sightings to his group, JellyWatch.org, to help move the research along. Gershwin, meanwhile, worries that waiting may make it too late to stop the invasion, if it is indeed happening.
"We're conducting this enormous global experiment, damaging the oceans, and the ocean is our life support system," she said.
"As crazy as it sounds, I think humanity needs a rethink," Gershwin added. "We need to really think about how important is that life support system, how important is food from the ocean to us. Are we comfortable polluting it and poisoning it and wiping it off the face of the Earth? Is that the result we want for our future and our kids and our grandkids?"