TUCSON, AZ (Tucson News Now) - Burning fossil fuels releases carbon into the atmosphere. This is a concern because carbon is one of many greenhouse gasses which trap heat in the lower atmosphere. This heat is what allows Earth to be habitable for plants and animals. However, too much heat can change weather and climate patterns, impacting where flora and fauna can survive.
Carbon is found in all life forms, such as plants and animals. Fossil fuels are made of plants and animals that passed away millions of years ago. After dying, the remains were buried and compacted, eventually turning into fossil fuels. Until recently, the left-behind carbon was safely stored away, locked in the untouched fossil fuel sources. By burning the fossils fuels, this carbon is now released in the atmosphere upsetting the natural balance of greenhouse gasses. The concern here is the rate at which this carbon is being released.
A new study recently published in Nature Geoscience found the rate even exceeds that of the last major carbon release event 66 million years ago, named the Paleocene-Eocene Thermal Maximum (PETM). While the cause of this ancient carbon release is unclear, it certainly was not human-caused. (Humans had not yet evolved on the Earth.) The additional carbon, and possibly other greenhouse gasses, in the atmosphere raised global average temperatures 5 to 8 degrees. But this change took many thousands of years. The gradual shift to a warmer world likely kept a mass extinction out of the fossil record.
Today, the rate of change may be much more dramatic, which is concerning since (1) plants and animals may not be able to adjust, prompting a mass die-off and (2) humans have built complicated and expensive infrastructure that is not easily moved to accommodate a warmer world, especially rising sea levels.
The image below from wunderground.com compares the temperature rise during the PETM, with a more gradual release of carbon, to our modern release of carbon from burning fossil fuels. During the PETM global temperatures rose about 0.025 degree every 100 years, versus the current and projected rise of 1 to 4 degrees every 100 years.
"We suggest that such a 'no-analogue' state represents a fundamental challenge in constraining future climate projections. Also, future ecosystem disruptions are likely to exceed the relatively limited extinctions observed at the PETM" writes the authors of the Nature Geoscience paper.
Bottom Line: We simply have no other comparison to how ecosystems will react to such quick warming. The closest comparison was 66 millions years ago, but you can see in the data the numbers simply do not apply to today.