First published at Pearls and Irritations.
This is the second article in a two-part series. Read the first part here.
The heat and extreme climate records of 2023 shocked scientists. So where are we heading? Given current trends, the world will zoom past 2°C of warming and the Paris climate goal of limiting warming to 1.5-2°C.
Climate model scenarios similar to current policies project 2°C of warming before 2050; if James Hansen is right (see Part 1) and warming sharply accelerates, it could be a decade sooner. These outcomes will be driven by the high energy imbalance, continuing high emissions, the accelerating accumulation of heat in the oceans, and decreases in short-term aerosol cooling.
Several years ago a group of eminent scientists proposed a “carbon law”, which said that keeping warming to 2°C required emissions to be halved every decade from 2020 onwards, including a halving between 2020 and 2030, plus some carbon drawdown. Instead, the level of greenhouse gases and coal use both hit record highs in 2023. And the largest national fossil fuel producers plan to keep on expanding production As a result, current government plans worldwide will likely result in emissions in 2050 almost as high as they are today, according to the UN Environment Programme’s 2023 Production Gap report.
Other analyses are broadly consistent:
- The International Energy Agency finds that stated national policies will result in oil and gas production in 2050 as high as 2020; with coal halved.
- The OECD finds that a world economy four times larger than today is projected to need 80% more energy in 2050; and without new policy action and the global energy mix in 2050 will not differ significantly from today.
The intentions of the world’s five largest fossil fuel producers are clear — and civilisation-threatening — as reported by the UN:
- In China, oil production is projected to be flat to 2050, but gas will increase more than 60 percent from 2020 to 2050, while coal use will remain high till 2030 then decline sharply.
- In the United States, oil production will grow and then remain at record levels to 2050, and gas is projected to continuously and significantly increase to 2050; whilst coal will drop by half.
- Projections for Russia are available only to 2035, with coal and gas production projected to increase significantly, while oil remains flat.
- In Saudi Arabia, oil production is projected to grow by 26 to 47 percent by 2050, with gas up 40 percent between 2019 and 2050. Together they make up half of the Saudi economy.
- And in Australia, one of the world’s top two liquified natural gas and coal exporters, gas production is projected to stay above the current level for the next 15 years, with coal remaining high over the same period, above 450 million metric tons annually.
We are heading towards 3–4°C.
This outlook suggests Earth is heading towards 3°C of warming and perhaps a good deal more, because current climate models which project warming of around 2.7°C do not adequately account for all the system-level reinforcing feedbacks.
In 2021, the pre-eminent UK international affairs think-tank Chatham House said a “plausible worst-case scenario” is 3.5°C or more, which could be an underestimate if tipping points are reached sooner than the orthodox science suggests. This now seems to be the reality.
A clear majority of scientists expected warming of more than 3°C, and 82% expected to see catastrophic impacts of climate change in their lifetime, according to a 2021 survey by the journal Nature.
Questions about the size of the aerosol forcing, and the related issue of how sensitive the climate is to changes in greenhouse gases, remain an issue of scientific contention.
New climate history research published in December 2023, based on a study of the last 66 million years, concluded that global temperature may be more sensitive to CO2 levels than current models estimate. It showed that the last time CO2 levels were as high as today was around 14 million year ago, which is longer than previous estimates, and that climate sensitivity — the amount of warming resulting from a doubling of atmospheric CO2 — may be between between 5°C and 8°C, compared to the IPCC orthodoxy of 1.5–4.5°C.
The level of greenhouse gases is currently around 560 parts per million, double the pre-industrial level. Some of those gases such as methane are short-lived so this level of forcing is not written in stone, but nevertheless if Hansen et al. are right that a doubling may lead to around 4–5°C of warming, then another 30 years of high emissions means humans will have created an increasingly unliveable planet.
Has the impact of aerosols been widely understood? In what the New York Times described as “an eye-opening Nature commentary”, Geeta Persad and her colleagues wrote in late 2022 that “overall, vast emissions of aerosols since the start of the industrial age have had a profound cooling effect” and that without them “the global warming we see today would be 30 to 50 percent greater”, warning that “the impacts of aerosols on climate risk are often ignored”.
In 2018, a group of eminent scientists explored the potential — once warming had exceeded the 1.5–2°C range — for self-reinforcing positive feedbacks in major elements of the climate system to push passed a planetary threshold that would prevent temperature stabilisation, and drive the system to a “Hothouse Earth”. They warned that “we are in a climate emergency… this is an existential threat to civilisation”.
The 2023 State of the Climate Report: Entering uncharted territory warned of: “potential collapse of natural and socioeconomic systems in such a world [of 2.6°C warming] where we will face unbearable heat, frequent extreme weather events, food and fresh water shortages, rising seas, more emerging diseases, and increased social unrest and geopolitical conflict.”
Whatever the words, the understanding is widely shared that contemporary nations and societies, and likely the global social system, are heading towards collapse. “If we carry on the way we are going now, I can’t see this civilisation lasting to the end of this century”, says Professor Tim Lenton. The US Defence Secretary Lloyd Austin III calls the risks “existential”.
Opening the Innovation Zero Congress in London in May 2023, Potsdam Institute Director Prof. Johan Rockstrom described the path we are on:
“2.5°C global mean surface temperature rise is a disaster. It’s something that humanity has absolutely no evidence that we can cope with… [There] would be a 10-metre sea-level rise. There would be a collapse of all the big biomes on planet Earth – the rainforest, many of the temperate forests – abrupt thawing of permafrost, we will have complete collapse of marine biology… Over one-third of the planet around the equatorial regions will be uninhabitable because you will pass the threshold of health, which is around 30°C. It’s only in some parts of the Sahara Desert today that has that kind of average temperature.”
Chatham House’s Climate Risk Assessment 2021 concludes that by 2050 global food demand would be 50% higher, but crop yields may drop by 30%. As desertification spreads across the dry sub-tropics, and one-third of the planet experiences unprecedented heat, it is not difficult to see why they concluded that cascading climate impacts will “drive political instability and greater national insecurity, and fuel regional and international conflict”.
What is worse is the setback to climate action posed by current conflicts and military posturing in Europe, the Middle East and east Asia, which are huge political distractions from dealing with the greatest threat to humanity, and all of which have the potential to spread more widely.
To maintain military flexibility, the US insisted in 1997 that direct military carbon emissions be excluded from international carbon accounting. Those emissions, around 5 percent of the total global, are far less than the indirect emissions from conflict, as recent estimates here and here indicate.
Past, Current and Future Extents of the Sahara
Image: https://earth.org/data_visualization/the-past-present-and-future-
of-the-sahara-desert, based on Thomas and Nigam, 2018
(https://journals.ametsoc.org/view/journals/clim/31/9/jcli-d-17-0187.1.xml)
Projections show that by 2100 the expansion of the Sahara due to desertification will embrace Israel/Palestine, as well as spreading across the Mediterranean into Spain, Italy, Greece and Turkey (see map).
The Australian Prime Minister has finally spoken out about the escalating climate threat whilst inspecting damage from the recent Queensland floods: “All of this is a reminder that the science told us that climate change would mean there would be more extreme weather events and they would be more intense. And unfortunately, we are seeing that play out with the number of events that we’re having to deal with right around Australia”.
Just so, except that in common with leaders globally, the Australian government continues to have its head stuck in the sand about the real risks climate change now represents. It refuses to release an intelligence assessment of climate-security risks, and has fumbled a domestic climate risk assessment.
As a result, the community remains ill-informed and unprepared for what is coming.
