Climate change is now self-amplifying. Humanity can avoid speeding up the rate of climate change. Humanity can halt atmospheric temperature rise and its consequences, but not by reducing its emissions to zero in the next several years, even if that were feasible. All that would do is slow the rate of change down some. As is, the Earth's surface will become uninhabitable eventually. The question to ask is "How quickly?"
In workshops I have watched in the last couple years, climate scientists routinely state their belief that we will reach 2-2.5C degrees of average global atmospheric warming before we reach "net zero" carbon emissions in 2050. They also seem to think that we have started positive feedback loops of atmospheric temperature increase by heating the rain forests, the open ocean, the poles, forested areas, and permafrost. Some also think that those feedback loops are locked into the climate system. If so, those feedback loops can push temperature increase past 2.5C. I think they can work on their own from our current 1.2C of warming.
The choice of "tipping point" to describe the problem areas of the globe was a bad one. Once their amplifying changes start, some tipping points are reversible (like loss of rain forest to burning or plankton to pollutants) while most are not (like permafrost melt) over human timescales. The existence of a tipping point implies a sudden tipping over, but tipping point processes are fairly gradual in human terms, and their rate can accelerate or decelerate.
There is some consensus forming that the Arctic tipping point is past, but explaining what that means is confusing. We can expect ice-free summers in the Arctic in the coming decades. The ice losses amplify other processes like permafrost GHG release. The processes speed up atmospheric temperature increase. But I don't know if we can reverse the ice loss. There are some discussions out there about protecting the Arctic ice with geoengineering, but no studies of the feasibility of that possibility, and time is short.
Scientists recently discovered a new tipping point connected to a loss of cloud cover past a certain degree of warming. An estimate of temperature increase forced by that loss of cloud cover is an additional 8C. That tipping point is estimated to happen at about 6C of warming (I think). That estimate of the warming level that forces the cloud loss might be too high.
A couple years ago climate scientists began saying that real data had invalidated their climate models. Actual measurements show indicators (like Greenland ice melt) higher than models predicted and accelerating in their increase.
Scientists have revised model estimates for tipping points from higher levels of warming down to lower levels in the last decade. Every tipping point locks in some temperature increase. Some amount of temperature increase forces other tipping points. The tipping points can continue the temperature increase themselves (for example, melting permafrost can put greenhouse gases in the atmosphere itself, and the permafrost is already melting in today's climate). Tipping points also have other consequences (for example, melting of the West Antarctic ice sheet ruining farmland and drowning coastal cities) but my point is that acceleration of their processes occurs due to other processes (for example, Arctic ice melt can help indirectly release GHG's that contribute to droughts and forest losses which removes a carbon sink, increasing net GHG's in the atmosphere). Tipping points now begin to fall at only 1.1C, when in the past they were believed to occur only with more atmospheric warming.
Lines of evidence like I listed here lead me to think that we no longer have to force the atmospheric system for it to continue to warm indefinitely. However, we are continuing to force the system anyway, increasing the rate and acceleration of warming.
If I understand correctly, IPCC models used to calculate carbon budgets did not incorporate rate of change in global temperature forced by tipping point mechanisms (for example, permafrost as an an increasing carbon source). Instead, the IPCC used steady state models that ignored tipping point acceleration and extent and instead gave risk estimates of when some tipping points could be reached (whatever that means) in terms of atmospheric temperature increases forced by anthropogenic GHG's. The risk estimates served as signposts of what to avoid, and general consensus was to avoid warming past 1.5C.
Climate scientists have to answer:
"Are present conditions sufficient to force all tipping points to reach their final stage or is anthropogenic forcing necessary?"
They are hesitating, so it's an open question for a while longer for most people. Once the question is answered, climate scientists have to look at the rate at which tipping points force climate changes and provide strong models with real estimates. Those models can help humanity grapple with geoengineering questions about how to successfully cool the planet.
If you are wondering, countries that pollute (or are responsible for pollution elsewhere) have committed to reach "net-zero" by 2050, but the promises are worthless and the plans are corrupted by special interests. Actual carbon production continues to follow exponential growth. Nowhere in negotiated plans do countries commit to reducing their emissions to zero. Instead, emitters promise a balance of greenhouse gas production and removal that is not timely or feasible at scale with current technology (DACS, BECSS, reforestation, etc). The international government agreement to reach net-zero by 2050 is an obvious and stupid failure that is visible 28 years in advance.
There are no feasible plans seriously and widely considered from any source to prevent destruction of human civilization due to climate change within the century.
Technology can address the problem of climate change. We just don't have the technology yet. I think the solutions would start with nanotechnology similar to what Eric Drexler predicted in the 1980's.
Humanity suffers the harm of ecosystem losses or biosphere destruction as well. Humanity causes damage to the biosphere in multiple ways, not just through climate change. Humanity has to heal the biosphere and reverse climate change in order to survive on Earth.
Do you have responses to articles on the forum like: https://forum.effectivealtruism.org/posts/ckPSrWeghc4gNsShK/good-news-on-climate-change ?
Hello Linch.
Thanks for your comment. Sure, after browsing the post that you referenced, I have a response to it that I can share with you.
As I wrote already, tipping point mechanisms are not incorporated into IPCC carbon budgets. I don't believe that their potential forcings are integrated into policy models of temperature change due to anthropogenic emissions in general.
As information about actual changes to tipping points increases, estimates of risk of those tipping points forcing temperature upward increases, but there is still a delay between research findings and their integration into consensus belief in the climate science community. There might be different reasons in different cases.
Actual data shows some tipping points (arctic ice melt, permafrost melt, rainforest losses, Greenland ice melt, global wind patterns, West Antarctic ice melt) beginning their forcings now and at an accelerating rate.
Older models of changes in large natural systems like plankton populations or Greenland ic sheets (and available data about them) let steady state approximations of those systems seem reasonable over this century. However, because climate scientists see more changes than they expect at lower amounts of temperature change, those approximations are no longer reasonable.
I believe that the equilibrium climate sensitivity metric that the authors quote does not account for tipping point processes forcing temperature increases to any great extent. I also doubt its reliability even if steady state approximations for tipping points were reasonable, but I don't have answers for those doubts now.
The value of the ocean as a carbon sink has declined since the start of the industrial revolution. It will continue to decline, but at rates that are not well-studied yet. The authors of the "Good news" article expect atmospheric CO2 to decline as land and ocean sinks absorb it. However, anthropogenic global warming, other anthropogenic forcing of natural systems (for example, poisoning plankton with micro-plastic or burning down rainforest), and indirect climate interactions reduce the capacity of those sinks. How much and with what consequences will be observable over this century.
Global warming is well-studied in the sense that climate scientists can make broad statements about eventual impacts and suggest policies that will avoid the continuation of global warming mechanisms. Or rather, that is how it used to be. Now that tipping points are an immediate concern, climate scientists have to play catch up with actual global warming events and revise their estimates of eventual impacts as new amplifying mechanisms are measured in action and models are revised to include more features or greater detail. There is not enough consensus on tipping point mechanisms or their consequences between scientists working within governments and those with more freedom to speak. From what I can tell, there are, and might continue to be, peer-reviewed studies of alarming evidence for future climate change impacts that the IPCC will not mention in its policy guidance because of filtering by government editors.
The authors of the 'Good news on climate change' post say:
"...in order for us to follow SSP5-RCP8.5, there would have to be very fast economic growth and technological progress, but meagre progress on low carbon technologies. This does not seem very plausible. "
I disagree. To follow RCP8.5, there would need to be continuing economic and population growth but not technological progress sufficient to displace dirty technologies.
Nanotechnological architecture, product manufacture, and pollution clean-up (as originally envisioned by Eric Drexler in "Engines of Creation") has value because that hypothetical technology will allow mega-engineering projects over time frames of a few days or weeks. With large-scale nanotechnology applications, humanity can develop and deploy global geoengineering tools, test them, and remove them if they create more problems than they solve. Meanwhile, our civilization can use nanotechnology to achieve energy efficiencies and clean technologies that replace dirty technologies and clean up their pollution quickly, within useful time frames of just a few months. Fantastic!
With nanotechnology in use, humanity doesn't have the problems of:
* poverty preventing change-over to low-GHG technologies at scale.
* using high-GHG technologies to manufacture low-GHG technologies at scale.
* acquiring the source materials for the enormous manufacturing output required
* taking longer than the time available to produce and integrate low-GHG technologies into our economies.
* industrial and construction waste damaging the biosphere or increasing global warming.
Nanotechnology helps humanity avoid the scrooge path of increasing its population while resource limits, biosphere losses, and climate change reduce quality of life. I would not propose nanotechnology as a solution, but humanity needs working methods of cooling the planet and thriving in the meantime. Nanotechnology would work.
If nanotechnology of the sort I'm describing becomes a reality, then that will be the news that the post authors want.