By John Englander, oceanographer and author
The new IPCC Climate Report (Intergovernmental Panel on Climate Change) is making headlines. At almost 4,000 pages, it is clearly intended for scientists. Fortunately, the 42-page Summary for Policy Makers is quite readable and understandable, but also warrants explanation.
Here is my summary of this Sixth Assessment. Since the last edition nine years ago, the hundreds of scientific experts can now state unequivocally:
- Average global temperature is 1.2 degrees Celsius (2.2 Fahrenheit) warmer than pre-industrial, primarily due to the heat trapping “greenhouse gases” from burning fossil fuels over the last century plus.
- Despite prior warnings and modest efforts to slow the warming, the warming continues –and is actually accelerating. We continue to break temperature records going back to 1850.
- Effects that can be directly attributed include heatwaves, rampant wildfires, drought, deluge rainfall, catastrophic floods, melting of the glaciers, crop failures, and the very early stages of sea level rise.
- The melting of the Greenland ice sheet is a primary factor slowing the Gulf Stream, the well-known feature of the giant “conveyor belt” current of the Atlantic Ocean (the AMOC). The slowing and potential collapse of the AMOC will add to the severe destabilization of the weather patterns the world has assumed to benormal.
“We still have time to avert disaster” is a common headline in mainstream media. Unfortunately, that’s misleading.
Pundits are focusing on the possibility that we can keep the warming to just an additional 0.3 degrees Celsius, a half of a degree Fahrenheit by mid-century. It will be VERY difficult to achieve that. But even if we achieve that goal, all the effects of warming will be considerably worse than what we are experiencing now. In other words, the less-than-worst case scenarios do not mean we have averted disaster.
The IPCC scenarios can be simplified into a few levels of temperature increase, all in comparison to the pre-industrial global average (roughly 1850-1900) prior to humans significantly altering the atmosphere.
Our ability to limit the warming to one of these levels depends on how radical our efforts are to slow the emission of carbon dioxide, which correlates to temperature increase, which slowly melts the ice sheets and raises global sea level. At the risk of oversimplifying, here are the three target levels and my interpretation of the effects.
- 1.5 degrees Celsius above pre-industrial (2.7 degrees Fahrenheit) by mid-century. We are already at 1.2 Celsius (2.2 Fahrenheit). Stopping it at just three-tenths above present will be EXTREMELY difficult. Many experts doubt that it’s even possible. Efforts will have to be way beyond present day efforts to get off fossil fuels. Yet, we should try. It means cutting CO2 emissions worldwide in half by 2030 and getting to zero net emissions by 2050. However, even if we stop the warming at this level it will still be about 20% worse than at present. That means more heatwaves, fires, flooding, melting ice and sea-level rise than at present.
- 2 degrees Celsius(6 Fahrenheit) is a more realistic goal than 1.5, but also will be extremely hard to achieve. Doing so will require a “wartime effort” that will change society all over the world, yet we should try. At that level we can expect all of the current effects to be dramatically worse than what we are seeing now.
- 3 – 4 degrees Celsiusis where we are headed on our current path – that’s roughly 5-7 degrees Fahrenheit. That would essentially be about triple the amount of warming that we are now experiencing. At this level the effects will be deadly with almost certain massive species die-off, collapse of the Greenland and West Antarctic ice sheets causing catastrophic sea-level rise, ocean acidification, and tipping points that could threaten our own survival.
I cannot stress too strongly that we need to do three things simultaneously:
- Slow the warming as the most urgent international priority, most directly by reducing the level of “greenhouse gases” in the atmosphere,principally carbon dioxide and methane.
- Design and build to be more resilient to the heat, heavy rain, strange storms, and wildfires we are experiencing globally, which will get worse as the planet continues to warm.
- Start planning and adapting for much higher sea levelthat is now inevitable and will become even more noticeable and much more severe as early as mid-century.
We’ve been warned about this for more than three decades. It’s time to face reality.
We have warmed the planet 1.2 degrees Celsius due to unrestrained use of fossil fuels. That excess heat will change the Earth for centuries, and in fact millennia. It is a fantasy to think we will recover and return to the relatively stable climate of a century ago.
What this new IPCC report shows is that even under the best-case scenario we will live through even more devastating effects than what we are seeing now. Hoping that technology or some other miracle will solve this ignores the severity of the situation. We are already at a point of danger. It’s time to sober up, be realistic, and demand action.
John Englander is an oceanographer and author of MOVING TO HIGHER GROUND: Rising Sea Level and the Path Forward and High Tide on Main Street. www.johnenglander.net
Twitter @johnenglander FB: johnenglander sea level rise.
“The Invading Sea” is the opinion arm of the Florida Climate Reporting Network, a collaborative of news organizations across the state focusing on the threats posed by the warming climate.
