Jurassic Heat -

A Melting Planet

I read the news about Greenland. It left a hollowness, like some part of me had gone missing. But the news wasn’t new at all. Anyone paying attention over the past decade has watched the decline of the Greenland ice sheet — a sad drama unfolding in slow motion, dragging the unwary into a future they don’t fully comprehend. The number that best categorized the news for me was six billion. This number described the tons of water lost each day over an extra hot July weekend in Greenland.

I imagined the soft, mushy feel of walking over the decaying layer of surface ice. Rivulets of water collect into trickles, and trickles turn into streams, all flowing downslope under the pull of gravity. Glacial crevasses open up, and the streams are sucked below the surface, joining thousands of other streams. Together, these streams feed vast underground rivers cutting along the base of the ice sheet, eventually gushing into the North Atlantic Ocean and the Labrador Sea. The water is like sweat squeezed out of the ice and snow, dripping off Greenland, carrying away its lifeblood.

Only several years ago, in August of 2019, temperatures rose above freezing at the highest point on Greenland’s ice sheet. This super warming was the third time such an event has occurred in the past 700 years. The results were impressive. The island lost 12.5 billion tons of ice in a single day. Remember, there is enough ice in Greenland to raise global sea levels by about 6 meters (20 feet) if it all melts.

Point of No Return

The intricate and delicate climate controls used by Mother Earth involve myriad feedback loops. Nothing happens in isolation; change begets more change. White ice sheets reflect most solar radiation away from Earth and back into space. But higher global temperatures melt the ice. As ice disappears it exposes the dark land below, which is less reflective, and Earth heats even faster. Climate is the product of thousands of feedback loops that help absorb and distribute heat from the Sun.

The Greenland ice sheet is caught in an Anthropocene heat trap, allowing it to melt from both above and below at unprecedented rates. Some researchers believe we are at the point of no return. It is a sobering message. Even if, through some miracle, humanity stumbles and staggers into a world of net zero emissions, the Greenland ice sheet will still disintegrate. Its lifeblood will return to the oceans of Earth, and billions of us will have to migrate inland.

We let the genie out of the bottle, and it granted us our three wishes: energy, more energy, cheap energy. The phrase that comes to mind is, be careful what you wish for; you may get it. Portugal and Spain are on fire, and the United Kingdom swelters under the highest temperatures ever recorded in this small island kingdom.

Jurassic Heat

Morning arrives again. I read the news and see that 100 million Americans are living under a heat alert, with temperatures in some unfortunate towns reaching 115 degrees F. Almost a third of the people in the USA search for relief from the heat and shelter from the Sun. I cast my thoughts back to the summer of 1997 when I returned to Houston, Texas, after two years in England.

Upon landing, the pilot announced that local temperatures were close to 100 degrees F. Even armed with this information, I wasn’t prepared for the heat and humidity. As I exited the arrival doors at the George Bush Intercontinental Airport, I smacked into a brick wall of heat. It felt solid. My time away had made me soft. But the experience drove home the oppressive, suffocating effects of heat on the human body and why without air conditioning, Houston would grind to a halt. At the time, I didn’t appreciate the irony of burning fossil fuels to create the electricity necessary for an air-conditioned metropolis.

News stories tell us these excessive heat waves and heat domes over the past several decades are not normal. But normal is a relative term. Global warming is indeed breaking the norm of the past several hundred years. However, in the long arc of geological time, we are simply returning to the norm.

In total, Earth spent about 670 million years out of its 4.5 billion-year history in glacial periods. Glacial periods account for a mere 15% of Earth’s existence. Normal is a hot, mostly ice-free planet. This normal, ice-free Earth supports large inland seas, and vast areas of continental coastline are underwater.

Our view of normal stems from the fact that Homo sapiens evolved during one of the relatively rare glacial periods in Earth’s history. This particular period began about 34 million years ago. So, from a human standpoint, global warming pushes us from a normal ‘cool earth’ state toward an unwelcome ‘warm earth.’ However, from a geological perspective, global warming is moving us back to the Earth’s normal warm state.

The fact that a warm planet is normal doesn’t provide humans with any comfort because approximately 33% of the world’s population lives within 100 meters of sea level. An ice-free earth submerges the first 66 of those 100 meters under the ocean.

About 55 million years ago, Earth’s average temperature surged to a peak, reaching 84 degrees F (29 degrees C). Global temperatures were a staggering 25 degrees F higher than today. This peak formed the culmination of a warming trend that started in the Early Jurassic and continued building for about 150 million years. Jurassic heat was the beginning of one of Earth’s longest warming trends. But keep in mind the “cold” starting point in the early Jurassic was still warmer than today.

The planet is returning to its normal warm-earth state. But there is something very abnormal about our Anthropocene warming dilemma. The current rate of climate warming far exceeds anything in the geological record. The Paleocene Eocene Thermal Maximum 55 million years ago was the culmination of 150 million years of change. At our current rate of heating, we will return to a superheated Eocene-like world in about 1,500 years, not 150 million years.

Paleontology has uncovered numerous mass extinctions throughout geological history. These events record massive assaults on life where as many as 90 percent of all species pass into the void of extinction. But they all carry a common message. When the rate of climate change is too rapid, evolution fails to keep up and life disappears. It’s something to think about.