Let’s take a walk down History Lane. It’s 66 million years ago and our mammalian ancestors are cowering in the underbrush as dinosaurs rule the world. A flash appears in the sky, then there is a monstrous explosion — and the world changed forever. In the ensuing climatic cataclysm, clouds of dust and debris obscured the sun, and 76% of all animal species went extinct.
After a while, Earth conditions returned to livable, and mammals, having survived the catastrophe where giant lizards hadn’t, evolved into a species with enough dexterity and mental acuity to use silicon-based machines to write cogent essays on the past — and the future — of its kind.
The dinosaur-killing episode was one of 5 major extinction events in the past half billion years, and the only one in the last quarter billion years. The one previous was 252 million years ago and is known as the Great Dying because, by various estimates, 90% to 96% of all species vanished. The cause, until recently, was unknown.
A Smoking Gun
Until the late 20th century, the cause of the extinction event 66 million years ago was unknown. Then a 180 kilometer wide crater was discovered at the edge of Yucatan Peninsula in Mexico that provided the critical clue: A bolide (probably a comet) weighing at least a quadrillion kilograms had collided with Earth. Pursuant to this discovery, scientists searched for evidence of a similar collision 252 million years ago; none was found.
After years of perplexing scientists, a cause for the Great Dying has been discovered: measurements of isotopes of carbon and oxygen from the extinction period have confirmed that the carbon dioxide in the atmosphere tripled in a geologic eye-blink. The temperature rose about 11 F (note: 11 F means 11 units on the Fahrenheit scale, or 6 C; an actual temperature of 11 degrees Fahrenheit is denoted 11° F, which is -11° C). This was enough to cause a climate disruption sufficient to produce the extinction rate noted.
But why did atmospheric carbon dioxide triple?
No. Our mammalian ancestors did not suddenly discover how to burn fossil fuels. Rather, extensive lava fields in Russia reveal that there was a massive volcanic eruption that spewed, as well as lava, carbon dioxide and other greenhouse gases.
Today’s atmospheric carbon dioxide concentration is about 45% higher than at the start of the industrial revolution (mid-1800s). So we are now about one-sixth of the way to tripling atmospheric CO2 in a short time.
Carbon Dioxide In The Atmosphere Shows Sudden Decline
In the last month, carbon dioxide readings on Mount Mauna Loa in Hawaii have dropped from about 410 parts per million (ppm) to near 407 ppm. Is the Paris agreement already working? Is this the end of global warming?
‘Fraid not. Carbon dioxide’s swoon has a simple explanation: It’s summer in the northern hemisphere, where most of the Earth’s land mass is located.
The flourishing flora of summer soaks up carbon dioxide; there is a peak in May, followed by the annual decline. The general trend of a two ppm increase per year is still in tact.
Scientists Have A Cow Over Crumbling Ice Shelf
A peninsula extends north from Antarctica (there’s really no other direction to go when you’re at the south pole) towards South America. Surrounding this land mass is an ice shelf — the Larsen Shelf — which has several components. Parts A and B started crumbling in the mid-1990s, and now Larsen C has broken apart, with a titanic, Delaware-sized piece dropping off into the sea.
The process is called calving, and the new iceberg will have minimal DIRECT effect on sea level as it melts, since only 10% is above the water. However, ice shelves hold back the glaciers on land. Whether the newborn gentle cow will unleash a raging bull of a glacier collapse is unknown at this time.
US House Of Representatives Recognizes Climate Change
The US Congress passed, by a wide margin, a defense appropriations bill that recognizes climate change as a matter of “national security.” Given the arcane procedures of American legislation, this bill is far from being enacted into law, but it’s a ray of clarity amid the murkiness in the wake of the US announcement that it will withdraw from the Paris agreement.
Everyone is familiar with inflection points — points of significant change. Suppose you have an airline flight. If you arrive 10 seconds before the door closes, you fly; ten seconds after it closes, you wait for the next flight.
One obvious inflection point in the atmosphere is the freezing point of water. Below, you skid on the ice; above you just slosh through water.
Tropical cyclones form when the water is warm enough to support vigorous instability. The inflection point is 26° C (79° F).
The temperature of the ocean east and southeast of Hawaii is generally just below the inflection point in the summer. However, last summer the temperature rose above the inflection point and Hawaii was threatened by several tropical systems. This year, the temperature is back to near normal, and storms heading in the direction of Hawaii — like the currently dissipating Fernanda — will bring only some rain to the islands.
June Temperature Third Warmest
NOAA’s temperature analysis indicates that June 2017 was third warmest in the 138-year temperature record. The first half of the year was second only to the El Niño year of 2016. Record warmth was scattered around the globe, while there were no locations of record cold. If the last El Niño cycle is a guide, a period of apparent leveling off of temperature is likely.
The long-term increase in temperature is clear from the temperature record. The rate of change of temperature from the last El Niño to the recent one was steep. Scientists will be watching closely to see what temperature trend emerges in the next few years.