This winter was the warmest on record. In my area, the lake did not freeze and I had to shovel the driveway just a couple of times, and with more than a couple inches of snow. Canada’s winter was almost 10 degrees Fahrenheit warmer than normal. The U.S. was more than five degrees warmer, with many states, including New York, recording record warmth. That is huge. 

We have documented in this blog how last year broke records for global temperatures on most days. Now, for the past year, the ocean temperature every single day broke the delay record. These records are still being broken every day. The difference now is that we are breaking records by wide margins that were set just last year, also then by a wide margin. 

The oceans are our climate engine. A bit of simple science explains why. Soil is a good insulator. At just a few feet of depth land generally does not freeze. By ten feet, its temperature is about constant year-round. Deeper yet the temperature actually begins to increase, with the molten core generating constant heat a couple of thousand kilometers below the surface. 

The Earth’s land above and below water then acts as a pretty good insulator. It does not absorb much heat from the air or water above it. The land surface temperature, typically measured at a two meter height, warms up quickly when the sun is out and cools down quickly when the sun goes down. We all experience that change in temperature over the day and night because we all live on land. 

If we lived on the ocean, though, we’d notice a far smaller change in the temperature between day and night. The oceans absorb the sun’s rays and distribute them not over the first few inches of land’s surface, but through the first thirty feet or so of water depth. This first thirty feet then gives back some of that sun’s energy at night. Anyone who lives near a large body of water is well aware of the moderating effect of a mass of water on local temperatures. 

A boundary called the thermocline exists at that thirty foot level. Below the thermocline, ocean water is colder. When heat builds up in the oceans, it is most pronounced above the thermocline, and can cause the thermocline to descend deeper. This larger body of warmer water above the thermocline causes the El Niño that we recently experienced. The warm water eventually dissipates toward the poles, the thermocline rises, and everything pops back to normal, usually. 

However, this current trend in ocean heat absorption and temperature rise is almost unspeakably profound. I don’t like the term “gobsmacked”, but it might apply here. We had a warm ocean year before, back in 2016. But last year blew that out of the water (pun intended), and this year well exceeds last year. 

The ocean also experiences a positive feedback loop. As oceans warm, there is less surface ice, primarily on the Arctic and Antarctic Oceans. The white color of ice reflects the Sun’s energy and hence hinders ocean absorption. But, as oceans warm, less ice forms, and the oceans thus absorb even more energy than normal. This so-called albedo effect has led to warming in the polar regions and even the disruption of heat-distribution mechanisms such as the gulfstream. 

These combined effects of a huge heat sink and storage system, with oceans constituting 70% of the Earth’s surface, and with the albedo effect accelerating ocean warming, all combine to explain why the Earth is rapidly warming. 

Of course, people who populate media content most all live on land, so observations in the popular press have been rather terra-centric. If marine life could talk and write, they’d tell a mare-centric story of oceans warming almost a degree Celsius over the past forty year average, and almost two degrees since 1880. A two degree change in an ocean system that hovers around 20 degrees on average is unprecedented. 

Okay, a two degree Celsius, or almost a four degree Fahrenheit temperature increase for the oceans does not sound too extreme, does it? While four degrees Fahrenheit might influence whether I wear a sweater or a jacket in the fall or spring, ocean temperature causes other changes that are far more profound. 

As the oceans warm, they melt more ice in Greenland and Antarctica. Of course, ice floes also melt earlier and faster, but that melting is not problematic just as the melting of ice cubes in an overfilled glass will not cause water to spill out as they melt. But, land-based ice-melts raise the ocean’s levels. Further, warmer ocean water is less dense, which causes the oceans to expand and sea levels to rise more. That effect is profound. It won’t affect me on Lake Champlain because we are still a hundred feet above sea level. But, at one time my area was under water. If surface ice melted, the oceans would rise by about 450 feet above the ice age level. Sea level rise won’t affect my area for centuries, but it will certainly affect the Eastern Seaboard, Florida and Louisiana, and parts of Texas and Alaska. Island nations such as Tuvalu and some coastal nations will disappear entirely. 

In addition, a warming ocean holds more energy and causes more water to evaporate into the atmosphere. Water molecules are lighter than nitrogen and oxygen molecules, so more water vapor in the air reduces its density. The weather we experience is driven by differences in air temperatures and densities. Warming oceans mean far more frequent and powerful storms driven by these differences in air pressure and temperature. 

The temperature of our atmosphere is apparent to all. That explains our growing interest in air temperatures. But, what we should really be following is the temperature of our oceans. That’s where things are really heating up. And it’s where records have been broken every single day for the last year, with no signs of abating. This is not just El Nino. Granted, ocean warming in the Pacific Ocean mitigates as some of this ocean warmth dissipates toward the poles. But, as the ocean continues to warm, we may find ourselves in periods of El Niño and El Gran Chico, rather than La Niña and El Niño. The warm, wet, and weird winter we just experienced may become the norm, punctuated by even warmer, wetter, and weirder winters. Something big is happening.