Opinion: Time to re-think the climate change challenge

August 16, 2018 by Will Steffen, ScienceNordic
There is likely to be much more at stake in transgressing the Paris climate targets than just a slightly warmer planet. Credit: Shutterstock

The climate change challenge has fallen into a familiar pattern – more research papers on climate change, another COP (Conference of the Parties) meeting, more pledges by the world's governments to do something, continuing rises in greenhouse gas emissions, worsening extreme weather events, and so on and so on.

It's time we re-think the nature of this challenge.

That's just what a group of Earth System scientists did in our recent paper "Trajectories of the Earth System in the Anthropocene", published in the Proceedings of the National Academy of Sciences.

The paper could have been titled, in more reader-friendly language, "Where on Earth are we going?" Still, it captured media attention around the globe.

The paper challenges the almost universally accepted framework that human emissions of will always be the dominant driver of , no matter what trajectory climate change takes in the future. That is, the more greenhouse gases we emit, the higher the Earth's average surface temperature rises.

This rather linear view of the climate system – or more appropriately the Earth System – may be fundamentally flawed.

A radical perspective of the Earth system?

Our article offers a different perspective – that the Earth System may behave as 'complex system', with well-defined states and transitions between them driven largely by feedback processes within the system, not only by 'external' drivers. This perspective is not as radical as it sounds.

The Earth System has behaved this way in the recent past. The regular oscillations between ice ages and warm periods – like our current warm period, the Holocene – comprise a good example. The heavy lifting in the transitions between these states is done by feedback processes within the Earth System, not by the external forcing due to small changes in Earth's orbit.

We argue that our current, very high human emissions of greenhouse gases could activate some important feedback processes within the system.

Examples include melting of Arctic summer sea ice that accelerates warming in the north, increasing wildfires in the boreal forests and Amazon rainforest that release more carbon dioxide to the atmosphere, and the melting of permafrost in Siberia, which could release vast amounts of methane, a , to the atmosphere.

A domino effect to a Hothouse Earth

Our analysis points to a risk that if enough of these feedback processes are activated, they could act like a row of dominoes that would form a global cascade.

Ultimately, such a feedback cascade could take the trajectory out of human control and irreversibly towards 'Hothouse Earth', with temperatures of four or five degrees centigrade above pre-industrial.

Such conditions would have massive impacts on humans, threatening the viability of contemporary civilisation.

How credible is this analysis?

Not only do we understand the nature of several of these feedback processes that have operated in the past, we are beginning to see signs of instabilities in some of these processes today. And we know that the Earth System existed in stable, much hotter conditions in the very recent geological past.

We can't yet put specific probabilities on the size of the risk that a planetary threshold could exist that might propel us into a Hothouse Earth. That requires more research. But we know enough about the nature of the Earth System that this risk needs to be taken very seriously.

There is likely to be much more at stake in transgressing the Paris climate targets than just a slightly warmer planet.

Explore further: Planet now at risk of heading toward 'hothouse Earth' state

More information: Will Steffen et al. Trajectories of the Earth System in the Anthropocene, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1810141115

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julianpenrod
1 / 5 (7) Aug 16, 2018
To conventionally deal with climate change involves admitting what causes it.
In fact, it's chemtrails that are responsible for the weird behavior of the atmosphere.
Chemtrailing began in the early Fifties, but they were invisible then. Even invisible, though, they caused the number of tornadoes per year to go from a nearly constant 180 per year to eight or nine time that number now. They also caused the formation of the first new cloud species, cirrus intortus, and the only December hurricane, Alice, in 1955.
The atmosphere appears to have become saturated with chemical in 1997, so new contributions precipitated out. That caused them to become visible. 1997 is also the year manifestations life the worst "el Nino event", the worst hurricane season, the Northwest Passage opening, the accelerated melting of glaciers, the warmest years and the formation of undulatuis asperatus began.
philstacy9
1 / 5 (7) Aug 16, 2018
Consensus science is the domino effect. Rethink climate change as left wing jihad.
howhot3
1 / 5 (3) Aug 16, 2018
Yeah, my theory on Chemtrails is that they are spraying the globe with vitamin B12. Think about it for a moment, and ask how is vitamin B12 getting into bread. B12 helps brainwashing functions of the dark shadow government that are broadcast on AM radio. Sometimes its disguised as church preacher, other times as a talk show. B12 once it's in your head can also produce manifestations of extreme fascists thinking that the deep shadow government wants. Through the mass brainwash of millions of loyal AM-radio listeners by B12 chemtrails by B12 bombers flying at high altitude, it has created this need for the deep shadow state fake religion like anti-science evangel types to emerge and practice the AM voodo radio rituals. Once the atmosphere was saturated with B12, it became part of the fish food supply. In fact, everything you eat now contains B12. They even make energy drinks with it now! How crazy is that??? Huge stuff!!!

howhot3
3 / 5 (2) Aug 16, 2018
Consensus science is the domino effect. Rethink climate change as left wing jihad.

Yeah, That's because everyone knows that B12 causes global warming when sprayed as a chemtrail! Fool.
Ghostt
5 / 5 (5) Aug 16, 2018
In this comment section: Poe's Law
howhot3
not rated yet Aug 16, 2018
In this comment section: Poe's Law

What? You don't believe in B12? The aeresol version? Such a dog... such a lurker...
howhot3
not rated yet Aug 16, 2018
You know this is just an observation, but have you ever noticed how the chemtrails are most heavily concentrated over the Red states? The flyover country? Maybe THEY are trying to alter the elections and make it seem like liberals are bad when it's really chemtrails making people think the other. That B12 is a very powerful vitamin and can pack a wicked effect on that bourbon hangover especially in the chemtrail form! This is all sooo deep state stuff... be forewarned.

leetennant
5 / 5 (3) Aug 16, 2018
In this comment section: Poe's Law


I fell for it. Sorry howhot3, you got downvotes. But that was no crazier than the real posts.
howhot3
5 / 5 (2) Aug 16, 2018
@leetennant; LOL. That just made my evening. Beware of the B12 chemtrails dude... so so deep state stuff ... ;-)

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