This is a stunning rate of temperature rise. Half a degree per decade. If temperatures continue to rise at this rate, the 2090s will average 4.5°F warmer than the 2000s, and 6°F warmer than the 1970s! And the temperature rise will almost certainly not remain constant. Due to humanity's accelerating consumption of fossil fuels, carbon dioxide concentrations in the atmosphere will accelerate their rise and temperature rises will almost certainly accelerate as well. 0.5°F/decade almost certainly represents an underestimate of how much temperatures will increase during the 21st century.
Humanity has never lived in such a rapidly warming environment. Ever. Nothing comes close in our planet's history except for the Paleocene–Eocene Thermal Maximum (PETM)
The PETM was a huge warming triggered by mass releases of carbon dioxide and methane from the oceans 55.8 million years ago. Temperatures soared by more than 5°C from what was already a warmer environment than the present. The average temperature at the North Pole was 73°F, comparable to Miami. For tens of thousands of years there was not one snowflake. Not one floe of ice. No frost. Anywhere.
So how does our present addition of carbon dioxide to the atmosphere compare to what happened during the PETM? Much research has been done in the last decade, and the scope of carbon releases during the PETM, and their speed compared to our own time has become clear.
And the comparison is not good.
Here is a graph showing carbon releases into the atmosphere. Our current additions of carbon to the atmosphere are already more than 5 times greater than during the PETM, and are continuing to accelerate as the developing world industrializes, and the developed world does very little. Projections show that our carbon emissions will nearly triple, to 15 times the carbon emission rates of the PETM.
Graph of net carbon emissions into the atmosphere from Scientific American:
And a sediment core sample showing the PETM:
Some highlights from Dr. Kump's article:
Until recently, though, open questions about the event have made predictions speculative at best. New answers provide sobering clarity. They suggest the consequences of the planet’s last great global warming paled in comparison to what lies ahead, and they add new support for predictions that humanity will suffer if our course remains unaltered.
But what surprised us most was that this gas release was spread out over approximately 20,000 years—a time span between twice and 20 times as long as anyone has projected previously. That lengthy duration implies that the rate of injection during the PETM was less than two petagrams a year—a mere fraction of the rate at which the burning of fossil fuels is delivering greenhouse gases into the air today. Indeed, CO2 concentrations are rising probably 10 times faster now than they did during the PETM.
But what surprised us most was that this gas release was spread out over approximately 20,000 years—a time span between twice and 20 times as long as anyone has projected previously. That lengthy duration implies that the rate of injection during the PETM was less than two petagrams a year—a mere fraction of the rate at which the burning of fossil fuels is delivering greenhouse gases into the air today. Indeed, CO2 concentrations are rising probably 10 times faster now than they did during the PETM.
Species extinctions are on the rise, and shifting climate zones have already put surviving plants and animals on the move, often with the disease-bearing pests and other invasive species winning out in their new territories. Unlike those of the PETM, modern plants and animals now have roads, railways, dams, cities and towns blocking their migratory paths to more suitable climate. These days most large animals are already penned into tiny areas by surrounding habitat loss; their chances of moving to new latitudes to survive will in many cases be nil.
Current global warming is on a path to vastly exceed the PETM, but it may not be too late to avoid the calamity that awaits us. To do so requires immediate action by all the nations of the world to reduce the buildup of atmospheric carbon dioxide—and to ensure that the Paleocene-Eocene Thermal Maximum remains the last great global warming.
I have to disagree with Dr. Kump in the last extract from his article. Calamity does await us. The scientific community has known for almost 50 years that our fossil fuel emissions will warm the atmosphere. And yet next to nothing has been done. During the 1970s we had our best chance of limiting fossil fuel emissions during the first energy crisis. We made some cosmetic changes, but no real reforms. During the 1980s we slept through the soothing lullaby of the Reagan administration's neglect of environmental issues. During the 1990s Clinton triangulated away any meaningful environmental and energy reforms, and failed to provide any leadership on the Kyoto Protocol. The second Bush administration's hostility to environmental and energy reforms has been told in many long accounts, and requires no further comment by me.
And now we have Tea Party fanatics who would rather send the Earth straight to hell than acknowledge scientific reality, blocking any reforms to increase energy efficiency, or environmental protection. The Tea Party fanatics even want to reduce study and research about Global Warming!
We've never missed an opportunity to miss an opportunity.
I don't see how we can avoid calamity. It's not just the USA--cheap, carbon rich coal is powering the development of China--lip service is paid there to global warming, and greenwashing in China may be more prevalent than in any other country. India, South America, and even Africa are expanding their fossil fuel consumption rapidly. Coal is cheap, almost everywhere, and the worst thing we can consume. Short term thinking conquers all.
It makes me sad. I live on a beautiful barrier island, St. Simons Island with my partner. It is beautiful, a great place to grow up and a great place to live.
By 3000 CE, all of this will be gone. My house and island will be under a warm, acid sea, so deep that the sun will be only faintly visible. Rising to the surface, no land will be visible. The same will be true for land where billions of people live now, and where billions get their crops and foodstuffs from. And we're doing nothing to stop it. And with the current trajectory of carbon emissions, and our refusal to face the situation squarely, the remaking of our fair planet into an acidic, hot, steambath of a world seems inevitable.
