The dire Reality of the Climate Crisis
Hanno Böck
CO2 Emissions (Fossil fuels and Industry, GtC/yr), Global Carbon Budget 2019
I call this the chart of epic climate failure
CO2 Emissions (Fossil fuels and Industry), Global Carbon Budget 2019
CO2 Emissions (Fossil fuels and Industry), Global Carbon Budget 2019
So where are we?
The world is around 1 degree warmer and we are increasingly seeing effects
Heatwave in Europe (June/July)
Bushfires and heat records in Australia
Politics
Paris Agreement (2015)
All nations in the world agreed to 3 degree of global heating
That is probably not the story you heard about the Paris Agreement
Nations agreed to the goal of limiting global temperature rise to "well below 2°C"
"pursuing efforts to limit the temperature increase to 1.5 °C"
But they have no plan how to get there
In the Paris Agreement nations commit to so-called Nationally Determined Contributions (NDCs), which are, in effect, voluntary actions
[...] even if all unconditional Nationally Determined Contributions (NDCs) under the Paris Agreement are implemented, we are still on course for a 3.2°C temperature rise
Temperature Rise
| Current (~) | 1 °C |
| Paris goal (ambitious) | 1.5 °C |
| Paris goal (minimum) | 2 °C |
| Paris NDCs | 3 °C |
| Current policy | 3-4 °C (or more) |
The Science and the IPCC
The IPCC summarizes results from climate science
2018 the IPCC published a special report on 1.5 degree warming
It had two main messages:
- There is a substantial difference between 1.5 and 2 degree warming
- 1.5 degree is still doable
1.5°C or 2°C
Coral Reef
Jim E Maragos, U.S. Fish and Wildlife Service, public domain
How many coral reefs will be destroyed?
| 1.5°C | 70-90% |
| 2.0°C | 99% |
Summers with an ice-free Arctic 10x more likely
| 1.5°C | every 10 years |
| 2.0°C | every 100 years |
Sea level rise by 2100
| 1.5°C | 0.40 meters |
| 2.0°C | 0.46 meters |
Population affected by extreme heat
| 1.5°C | 14% |
| 2.0°C | 37% |
What is needed for 1.5°C?
Around 50% reduction til 2030, carbon neutral by 2050
Is the IPCC telling the full story?
A lot of scientists are worried that the IPCC is overly conservative
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We find that climate models published over the past five decades were generally quite accurate in predicting global warming in the years after publication, particularly when accounting for differences between modeled and actual changes in atmospheric CO2 and other climate drivers.
Are you confused?
Climate scientists have underestimated climate impacts, yet their models have been surprisingly accurate.
Can that both be true?
Actually yes.
Global mean temperature predictions have been very accurate, however predictions on specific effects of climate change have underestimated outcomes.
Did scientists get climate change wrong? (Sabine Hossenfelder interviews Tim Palmer)
Climate scientists are saying we need to act fast to avoid the worst outcomes of the climate crisis, but we can still do it
They have been saying similar things many years ago
The science did not get more optimistic
How is that possible?
Negative Emissions
All 1.5°C scenarios and most 2°C scenarios assume negative emissions in the future
Plant trees
Planting trees is good, but it has limits and competes with other uses of land
We need to talk about Carbon Capture and Storage (CCS)
Storing carbon dioxide underground
CCS first entered the discussion in the context of new coal power plants, but it has largely been a failure
Today there are only a few CCS projects operating, most of them in the context of Enhanced Oil Recovery
Bio energy and CCS (BECCS)
Use bio energy and capture the emissions
Obviously it comes with all the problems that usually come with bio energy
Direct Air Capture
Directly removing carbon dioxide from the air
These machines will require lots of energy and it is questionable how fast this can be scaled up
Optimistic IPCC scenarios rely on technology that largely does not exist
Even if the technology works: How do you make that work politically and economically?
Feedback Loops and Tipping Points
Probably the most relevant criticism of the IPCC is that they have insufficiently considered the risks of tipping points and feedback loops
When warming causes more warming
Ice is bright, Water is dark
Albedo Feedback Loop
Ice reflects part of the sun's energy back.
When the ice melts less energy is reflected, the oceans heat up more.
Tipping Point
At some point systems may collapse independent of further warming
It is estimated that the West Antarctic Ice Shield is already collapsing, which will alone increase sea level by 1-3 meters in the long run
Risk of a Cascade of Feedback Loops
The "Hothouse Earth" study warns that even with 2°C warming such a scenario can plausibly happen
Trajectories of the Earth System in the Anthropocene, many authors, 2018
There is significant uncertainty around feedback loops
These are long-term effects, some of them expected to unfold over thousands of years
What needs to happen?
We need to stop burning fossil fuels, that much is obvious
We need to get rid of this
Building renewable energy is easier than what most people predicted
Step 1: Switch to carbon-free electricity
Step 2: Electrify everything
How much electricity do we need?
- 26 PWh/y: current world production of electricity
- 160 PWh/y: total world energy production
- 18-32 PWh/y: Petrochemical industry with CCU
- 43 PWh/y: DAC for negative emissions
Where should all that electricity come from?
It's not just energy
Do you know how cement is made?
CaCO3 = CaO + CO2
That is around 5 % of worldwide carbon dioxide emissions
Livestock is responsible for around 15 percent of greenhouse gas emissions
Is this a solution?
There are solutions, but this is not going to be easy
Geoengineering
Can we do something to counteract the warming from the greenhouse effect?
Solar Radiation Management
The most plausible idea is putting aerosols into the atmosphere
(This is reasonably well understood, as volcanoes do this)
This is not widely discussed yet and the IPCC explicitly excludes solar radiation management from its scenarios
Under normal circumstances considering to blast chemicals into the atmosphere sounds really crazy
If we end up in a situation where it is either this or a planet largely uninhabitable we probably need to have that discussion
Some people may think Geoengineering is an easy way out and a reason to avoid reducing emissions
There are a lot of wrong ideas about the climate problem
In a survey asking Germans what they think are effective actions to reduce personal CO2 emissions showed they have no clue
Excessively overestimated impact: avoiding plastic bags, regional food
Excessively underestimated impact: eating meat
Efficiency is a Lie
People tend to think:
If we have more efficient technology this leads to less energy use and less emissions
This is not what is usually happening
A VW Tiguan is twice as heavy as an original VW Golf and needs roughly the same amount of fuel
That is an absolutely amazing increase in efficiency!
It's just not helping the climate
Jevons Paradox
Rebound Effect
Efficiency does not automatically reduces emissions and may even increase them
A lot of the climate debate circles around having better technologies to solve this problem
There is nothing wrong with using technology, but it is simply not plausible that technical innovation alone will have any meaningful impact
The situation is dire
There is sometimes a thin line between saying how bad it is and making unsubstantiated claims
New York Magazine / David Wallace-Wells: The Uninhabitable Earth
This article was largely based on a scenario called
RCP 8.5
RCP 8.5 is the worst case climate scenarios in the 2013 IPCC report
It is sometimes referred to as "business-as-usual" scenario
This scenario assumes humanity will use 6-7 times as much coal in 2100 compared to today
This is not impossible, but it looks rather unlikely given the growth of renewables
Discussions about implausible scenarios and RCP 8.5 led to a calculation based on IEA predictions, which estimates 3 °C warming by 2100, but with a significant uncertainty range (1.9 - 4.4 °C)
Breakthrough Institute: A 3C World Is Now “Business as Usual”
While some of the extreme scenarios look rather unlikely, the upper end of a plausible business-as-usual scenario is still catastrophic and 2100 scenarios don't consider long-term effects
There is growing agreement between economists and scientists that the tail risks are material and the risk of catastrophic and irreversible disaster is rising, implying potentially infinite costs of unmitigated climate change, including, in the extreme, human extinction (see, e.g., Weitzman 2009). (IMF)
I do not want to dismiss extreme scenarios, but often when I try to get to the sources of such claims not much comes up
Guy Mcpherson thinks climate change will kill all humans within the next decade and there is nothing we can do about it
This is not supported by the science
Arctic News is a blog written by a person with the pseudonym Sam Carana
Sam Carana is more optimistic than Guy Mcpherson, he has a plan to stop it
Methane Clathrate Bomb
Methane Clathrate or Hydrate is frozen methane on the ocean floor
The Methane Clathrate Bomb hypothesis is the idea that these deposits could rapidly melt and evade into the atmosphere
There have been a few scientific publications on this, but mostly scientists think this is impossible
To be clear: Methane Clathrates are a real concern and one of the feedback mechanisms in the climate system, but they are a long-term concern
These doomsday predictions tend to be a mixture of taking extremely speculative research and painting it as definite, massively overstating certain effects and confusing long-term with short-term effects
There are many cranks on the Internet and you can brush this off as ridiculous, but this stuff is creeping into the mainstream
VICE/Zing Tsjeng: The Climate Change Paper So Depressing It's Sending People to Therapy
This paper was rejected by a scientific publication due to its poor quality
It is heavily citing the questionable theories we just talked about, one of its main conclusions is based on references to the Arctic News blog
Jonathan Franzen, New Yorker: What If We Stopped Pretending?
Our atmosphere and oceans can absorb only so much heat before climate change, intensified by various feedback loops, spins completely out of control. The consensus among scientists and policy-makers is that we’ll pass this point of no return if the global mean temperature rises by more than two degrees Celsius. Jonathan Franzen
That is not true
Some scientists think this could happen with 2 °C warming (e.g. the "Hothouse earth" study), but that is very different from a consensus
These doomsday predictions are not only problematic because they are wrong
"It is too late to do anything about it!"
Two very different claims, same conclusion
| Climate change is a hoax / not caused by humans / not so bad | Climate change will inevitably lead to doom |
| No change is needed | |
Climate change is not binary
We cannot avoid climate change - it is already here
But there is almost no scenario in which reducing emissions as fast as possible is not improving the situation
There is the idea that there may be a point of no return, a point where tipping points and feedback loops kick in and warming will increase on its own
Remember many of these feedback effects will happen over a very long time, particularly the melting of Antarctica and Greenland
Imagine a scenario where humanity needs to evacuate large areas due to heat and sea level rise
Or imagine having to deploy geoengineering technologies or massive numbers of air capture devices for negative emissions
Think about doing this over decades, centuries or millennia and wonder what is easier
Summary
The situation is really bad
It absolutely matters what we do about it
Ask yourself what you can do to stop this in 2020
