April's global average sea surface temperatures have checked in as the warmest on the books, per the Copernicus Climate Change Service, meaning the ocean's surface has notched 13 straight months of record heat.

The big picture: For years, the world's water bodies have been warming in deeper depths and at the surface, but the ongoing streak is breaking previous milestones.

• Air temps get all the attention when it comes to global warming, but the vast majority of extra heat trapped by greenhouse gases goes into the oceans.

The intrigue: This heat has consequences, since it provides more moisture and energy to storm systems, which then churn out greater amounts of precipitation over land.

• The record-warm oceans have a tie to an ongoing but weakening El Niño event in the tropical Pacific, but they aren't entirely tied to it.
• The spike in water temperatures and geographic reach of the heat, affecting every ocean basin, are simply too big to pin the blame on the natural climate cycle.

What they're saying: "Whilst temperature variations associated with natural cycles like El Niño come and go, the extra energy trapped into the ocean and the atmosphere by increasing concentrations of greenhouse gases will keep pushing the global temperature towards new records," Carlo Buontempo, director of the Copernicus Climate Change Service, said in a statement.