Our Limited Earth: Contextualizing Degrees of Global Warming
On Planetary Boundaries, Part II
“We’ve reached a point where we have a crisis, an emergency, but people don’t know that. …There’s a big gap between what’s understood about global warming by the scientific community and what is known by the public and policymakers.”
James Hansen, Renowned former NASA climate scientist, 2008
Here at map-collective, we have been focusing on the science surrounding the climate change planetary boundary to get an understanding of where we lie in this earth system and to uncover the actual state of the climate catastrophe, what it means, and our timeline.
A shocking report made by the Intergovernmental Panel on Climate Change, the Special Report 18, claims we have 12 years to cut emissions in half to keep our planet under 1.5℃ by 2100 with a probability of 66%. What’s even more shocking is that this report is overly conservative and that its message is lost with uncertainties and information overload. There are several flaws with the IPCC, which we will cover in another article. (1) The main point is that keeping the planet under 1.5℃ is a fantasy.
A more accurate assessment of our current climate conditions can be found in independent analysis in the peer-reviewed literature; however, connecting the dots can be difficult and time-consuming. Distilling the information, we conclude that main questions we need to know to make a reasonable judgment of the state of the climate catastrophe:
1. What temperature are we at now?
2. How fast is the climate warming?
3. Have we passed the carbon planetary boundary for “safe operating space for humans”?
4. What’s at stake?
What temperature are we at now?
1.3℃ Right now. 2.0℃ — 3.2℃ by 2100, guaranteed.
Currently, the mean global mean average temperature is experiencing a 1.1℃ above pre-industrial levels (1850–1900). (2) It should be noted that warming isn’t uniform as Europe is 2 degrees hotter, and the Arctic is 5 degrees warmer than they should be.(3)
More advanced research challenges the pre-industrial baseline widely used in climate research and all policy, including the Intergovernmental Panel on Climate Change. With this advanced methodology, researchers propose that we should use a global average temperature 1400–1800s more accurately represents the global mean surface temperature ratchet than the one used from 1850–1900.(4) This more holistic approach states that the pre-industrial temperature baseline is 0.2℃ hotter; therefore, the global mean surface temperature is actually at 1.3℃.
This number is unbelievably crucial to climate policy. Every tenth of a degree, celsius dramatically moves the timeframe and carbon budgets previously established.
How fast is the climate warming?
The most recent data shows an increase of 0.2℃ (±0.1℃) per decade, and as we move towards a carbon-free economy with the rise an additional 0.1℃ of renewables, we can see the reduction in aerosols which have been cooling the planet.(5)
If we could snap our fingers and get an environmentalist dream of no emissions for 2020, we can expect the same additional 0.3℃ (±0.1℃)rise for the next ten years reaching 1.6℃ (±0.1℃) by 2030, as the maximum warming occurs about one decade after a carbon dioxide emission.(6)
The aerosol unmasking effect would unfold leaving the planet with a rise of 0.5℃-1.1℃ increase by 2100 as the hopeful transition to renewable energy will remove aerosols from our atmosphere.(7)
Right now, we’re guaranteed a mean global increase of 2.0℃ — 3.2℃ by 2100 from pre-industrial temperatures. In a best case scenario forecast where carbon emissions cease by 2030, we get lucky on aerosol’s cooling impact, the Earth will warm 2.2℃.
**Important** This is only the case if our models are linear, which there’s evidence that they’re not. Feedback loops and tipping points are crucial to this conversation and will be covered more thoroughly in our next Planetary boundaries research article. Click here for an introduction to planetary boundaries.
Have we passed the carbon planetary boundary for “safe operating space for humans”?
It’s uncertain, and it makes many scientists very uneasy. Our current and rising carbon emissions place us in the “zone of uncertainty” in the planetary boundaries analysis. This means they’re not sure either, but we need to pump the breaks. The zone of uncertainty leads to non-linear change; therefore, the temperature could rise more than 0.3℃ (±0.1℃) per decade.
A few years of zero action will most certainly push humans out of a safe operating space.
Key Takeaways for 1.3℃ Right now (2020). 2.2℃-3.4℃ by 2100 — (assuming linear change)
- Current policy believes that we have many more decades to reach 1.5℃ degrees, which are a fantasy at best. The IPCC Special Report states that a 1.5 degrees increase will occur by 2040, a 15-year mistake.
- Even with carbon neutrality, excessive carbon dioxide sequestration will be needed to walk back to a climate or 1.5℃, which is already dangerous for organized human life.
- Our current emissions, lack of a plan, and aerosol masking effect will take us out of humanity’s safe space in just a few years. 2025 or 2027.
- There is no carbon budget, we’ve already used it.
- The Arctic is already experiencing abrupt climate change and has passed the tipping point. (8)
- We are currently on the fast-baseline track, and it is estimated that there will be a 5℃ degree rise by 2100. A temperature that organized human life cannot adapt quickly enough (or in layman’s terms, billions of humans die).
- Tipping points reached.(9) Feedback loops have already begun, accelerating the temperature rise of the planet.
What’s At Stake
In short, life as we know it. Today, in 2020, climate change is already dangerous. Amazon, Arctic, Australia, and California have burned more than they ever have before. We’ve seen more hurricanes and mega-floods all over the world. We already live in an unpredictable, dangerous world, and it’s only going to get worse. The Greenland ice sheet will disappear, and all coral reefs will die, taking them the 500 million people’s primary food source. Water shortages will be felt worldwide, especially those who rely on snowpack and glacier melt. So on and so forth…
Below is a table that estimates the millions of exposed and vulnerable (poor people who live on <$10/day) in a scenario similar to the one we’re on (SSP 2- Medium challenges to adaptation and mitigation) in different temperatures.(10) Also, it’s key to note that 1000 million people are a billion people, i.e., 1,129 million people or 1.129 billion people will experience two indicators from the first column in just 1.5℃ in 2025. Can we even imagine this chart if it were to include the implications of a 5℃ temperature rise?
The point is plain and simple. The forecasted temperature rise is unacceptable. It will wreak havoc on life as we know it, our physical and mental health, and take away our opportunities to have a rich and prosperous life. It isn’t too late, but our window of opportunity is getting shorter by the day. Just as temperature rise is no longer linear, building resilience and drawing down carbon solutions and policy will not be linear. Exponential change must be met with exponential change to get this climate catastrophe under control.
“It is my experience that with few exceptions neither climate policy-makers nor climate action advocates have a reasonable understanding of the imminence of 1.5°C and its consequences.” David Spratt is Research Director for Breakthrough — National Centre for Climate Restoration
Written by Brendan Hellebusch for Map-Collective.com.
References:
1) IPCC is Underselling Climate Change https://www.sciencedaily.com/releases/2019/03/190320102010.htm
2) Copernicus , State of the Climate 2019: Surface Temperature https://climate.copernicus.eu/ESOTC/2019/surface-temperature
3) World Weather Attribution: Siberian heatwave of 2020 almost impossible without climate change https://www.worldweatherattribution.org/siberian-heatwave-of-2020-almost-impossible-without-climate-change/
4) Schurer, A. P., et al. 2018 “Interpretations of the Paris climate target.” https://www.nature.com/articles/s41561-018-0086-8
5) Xu Y. and Ramanathan V. (2017) Well below 2 °C: Mitigation strategies for avoiding dangerous to catastrophic climate changes https://www.pnas.org/content/pnas/114/39/10315.full.pdf
6) Ricke, K. L., & Caldeira, K. (2014). Maximum warming occurs about one decade after a carbon dioxide emission., 124002. https://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002
7) Samset, B. H. et al. (2018) Climate impacts from a removal of anthropogenic aerosol emissions. https://doi.org/10.1002/2017GL076079
8) Jansen, E., Christensen, J.H., Dokken, T. et al. (2020) Past perspectives on the present era of abrupt Arctic climate change https://doi.org/10.1038/s41558-020-0860-7
9) Steffen, Will, et al. (2018) “Trajectories of the Earth System in the Anthropocene.” https://www.pnas.org/content/115/33/8252
10) Intergovernmental Panel on Climate Change, Special Report Global warming of 1.5°C (2018) page 246 https://www.ipcc.ch/sr15/
