We Climate Scientists Won't Know Exactly How The Crisis Will Unfold Until It’s Too Late

We Climate Scientists Won't Know Exactly How The Crisis Will Unfold Until It’s Too Late Maridav / shutterstock

When we hold on to things for too long, change can come about abruptly and even catastrophically. While this will ring true for many from personal experience, similar things can happen at large scales as well. Indeed, the history of Earth’s climate and ecosystems is punctuated by frequent large-scale disruptive events.

When the air warmed and the last ice age was coming to an end, the continent-size glaciers – or ice sheets – stayed around for much longer than the climate would allow. Then parts of them collapsed in spectacular fashion. One such collapse – we still don’t know of which ice sheet – caused at least four metres of sea level rise per century and possibly also the following abrupt transition to a much warmer climate, only to be followed by an equally abrupt flip-flop between warm and cold conditions, before the onset of the stable climate we have enjoyed until recently.

This long period of stability seems to have ended already. Australia’s climate had been warming rapidly for many decades, and eventually the moment came when record-breaking extreme heat coupled with an exceptionally dry period created the conditions for a series of mega fires.

In all, the fires burned more than 20% of temperate broadleaf forests in New South Wales and Victoria, compared to less than 2% in a typical season. Many of the forests may never recover to their previous state. Other ecosystems may contain similar tipping points.

Predictive models are the lifeblood of climate science, and the foundation upon which political responses to the climate and ecological crisis are often based. But their ability to predict such large-scale disruptive events is severely limited.

For example, the massive scale of the recent Australian bushfires goes beyond what any model used by the Intergovernmental Panel on Climate Change (IPCC) has ever simulated – for the present or the future. In fact, one of us (Wolfgang) has published extensively on future wildfires, and his work found that fire activity in parts of south-eastern Australia would likely increase significantly by the late 21st century. In reality, much more widespread fires occurred some 70 years earlier than predicted.

We Climate Scientists Won't Know Exactly How The Crisis Will Unfold Until It’s Too Late Fires near Melbourne, January 2020. SS studio photography / shutterstock

This isn’t the only case where models used by climate scientists are inadequate. The IPCC’s estimates of how much CO₂ we can still emit to be on the safe side explicitly leave out many known large-scale disruptions or tipping points because of insufficient understanding or because models cannot capture them.

One such tipping event, the unravelling and eventual disappearance of the Amazon rainforest, may already be underway. A new study uses model-aided statistical analysis from past ecosystem collapses and comes to the conclusion that, once triggered, Amazon dieback could take as little as 50 years. Because we lack a full understanding of how exactly such a collapse might unfold, such models are not being included in future projections.

The IPCC’s recent report on the oceans and cryosphere (sea ice, glaciers and ice sheets) still doesn’t report the full possible range of sea level rise exacerbated by a possible collapse of the West Antarctic ice sheet. The IPCC’s range of 0.3 to 1.1 metres by 2100, dependent on emissions scenario, stays markedly below the worst-case scenario of 2.4 metres which resulted from an analysis of experts’ opinions. Zita Sebesvari, one of the report’s lead authors, has admitted that such a worst case scenario cannot be ruled out.

We know quite well that the climate we are about to create resembles that of millions of years ago, but we are mostly ignorant about how fast this will happen and what it means for humans and ecosystems. Yet scientists rarely point out the uncertainties in their predictions – in particular worst-case scenarios that are beyond the capability of models – and prefer to stick to the conservative but firm conclusions that can be drawn from well-established models.

To discuss highly uncertain but potentially catastrophic outcomes is often seen as political fearmongering. But basing the political response to the climate crisis on a series of safe-looking and – in their totality – apparently certain predictions is therefore painting a wholly inadequate picture of the potential risks that the climate and ecological crises pose to humanity and the biosphere.

We scientists need to proactively emphasise the uncertainties of our model scenarios, and that we don’t know for certain how severe the climate crisis will be, how rapidly it could unfold, nor how it will affect humans and ecosystems. In so doing, we must reassess how best science can contribute to climate policy in service of humanity.

We must have the humility to accept how much we do not know – including at what point it is too late to prevent catastrophic tipping points and the consequent large-scale disruption. Only then can we free the political response from operating according to conservative assumptions and mid-range scenarios, and base it firmly on preventing a worst-case scenario.

About The Author

Wolfgang Knorr, Senior Research Scientist, Physical Geography and Ecosystem Science, Lund University and Will Steffen, Emeritus Professor, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Climate Change: What Everyone Needs to Know

by Joseph Romm
0190866101The essential primer on what will be the defining issue of our time, Climate Change: What Everyone Needs to Know® is a clear-eyed overview of the science, conflicts, and implications of our warming planet. From Joseph Romm, Chief Science Advisor for National Geographic's Years of Living Dangerously series and one of Rolling Stone's "100 people who are changing America," Climate Change offers user-friendly, scientifically rigorous answers to the most difficult (and commonly politicized) questions surrounding what climatologist Lonnie Thompson has deemed "a clear and present danger to civilization.". Available On Amazon

Climate Change: The Science of Global Warming and Our Energy Future second edition Edition

by Jason Smerdon
0231172834This second edition of Climate Change is an accessible and comprehensive guide to the science behind global warming. Exquisitely illustrated, the text is geared toward students at a variety of levels. Edmond A. Mathez and Jason E. Smerdon provide a broad, informative introduction to the science that underlies our understanding of the climate system and the effects of human activity on the warming of our planet.Mathez and Smerdon describe the roles that the atmosphere and ocean play in our climate, introduce the concept of radiation balance, and explain climate changes that occurred in the past. They also detail the human activities that influence the climate, such as greenhouse gas and aerosol emissions and deforestation, as well as the effects of natural phenomena.  Available On Amazon

The Science of Climate Change: A Hands-On Course

by Blair Lee, Alina Bachmann
194747300XThe Science of Climate Change: A Hands-On Course uses text and eighteen hands-on activities to explain and teach the science of global warming and climate change, how humans are responsible, and what can be done to slow or stop the rate of global warming and climate change. This book is a complete, comprehensive guide to an essential environmental topic. Subjects covered in this book include: how molecules transfer energy from the sun to warm the atmosphere, greenhouse gases, the greenhouse effect, global warming, the Industrial Revolution, the combustion reaction, feedback loops, the relationship between weather and climate, climate change, carbon sinks, extinction, carbon footprint, recycling, and alternative energy. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook-icontwitter-iconrss-icon

 Get The Latest By Email

{emailcloak=off}

EVIDENCE

Marine Heat Waves Are Becoming More Common And Intense
Marine Heat Waves Are Becoming More Common And Intense
by Jen Monnier, Enisa
Improved “weather forecasts” for oceans hold hope for reducing devastation to fisheries and ecosystems around the world
Five Climate Disbeliefs: A Crash Course In Climate Misinformation
The Five Climate Disbeliefs: A Crash Course In Climate Misinformation
by John Cook
This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality…
Arctic Warming: Are Record Temperatures And Fires Arriving Earlier Than Scientists Predicted?
Arctic Warming: Are Record Temperatures and Fires Arriving Earlier Than Scientists Predicted?
by Christopher J White
It was a grim record. On June 20 2020, the mercury reached 38°C in Verkhoyansk, Siberia – the hottest it’s ever been in…
We Mapped The World's Frozen Peatlands And What We Found Was Very Worrying
We Mapped The World's Frozen Peatlands And What We Found Was Very Worrying
by Gustaf Hugelius
Peatlands cover just a few percent of the global land area but they store almost one-quarter of all soil carbon and so…
Will The Climate Warm As Much As Feared By Some?
Will The Climate Warm As Much As Feared By Some?
by Steven Sherwood et al
We know the climate changes as greenhouse gas concentrations rise, but the exact amount of expected warming remains…
Methane Emissions Hit Record Breaking Levels
Methane Emissions Hit Record Breaking Levels
by Josie Garthwaite
Global emissions of methane have reached the highest levels on record, research shows.
What The World Was Like The Last Time Carbon Dioxide Levels Were At 400ppm
What The World Was Like The Last Time Carbon Dioxide Levels Were At 400ppm
by James Shulmeister
The last time global carbon dioxide levels were consistently at or above 400 parts per million (ppm) was around four…
What An Ocean Hidden Under Antarctic Ice Reveals About Our Planet's Future Climate
What An Ocean Hidden Under Antarctic Ice Reveals About Our Planet's Future Climate
by Craig Stevens and Christina Hulbe
Jules Verne sent his fictional submarine, the Nautilus, to the South Pole through a hidden ocean beneath a thick ice…

LATEST VIDEOS

Five Climate Disbeliefs: A Crash Course In Climate Misinformation
The Five Climate Disbeliefs: A Crash Course In Climate Misinformation
by John Cook
This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality…
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
by Julie Brigham-Grette and Steve Petsch
Every year, sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 1.44…
What Is A Hurricane Storm Surge and Why Is It So Dangerous?
What Is A Hurricane Storm Surge and Why Is It So Dangerous?
by Anthony C. Didlake Jr
As Hurricane Sally headed for the northern Gulf Coast on Tuesday, September 15, 2020, forecasters warned of a…
Ocean Warming Threatens Coral Reefs and Soon Could Make It Harder To Restore Them
Ocean Warming Threatens Coral Reefs and Soon Could Make It Harder To Restore Them
by Shawna Foo
Anyone who’s tending a garden right now knows what extreme heat can do to plants. Heat is also a concern for an…
Sunspots Do Affect Our Weather But Not As Much As Other Things
Sunspots Do Affect Our Weather But Not As Much As Other Things
by Robert McLachlan
Are we headed for a period with lower Solar activity, i.e. sunspots? How long will it last? What happens to our world…
Dirty Tricks Climate Scientists Faced In Three Decades Since First IPCC Report
Dirty Tricks Climate Scientists Faced In Three Decades Since First IPCC Report
by Marc Hudson
Thirty years ago, in a small Swedish city called Sundsvall, the Intergovernmental Panel on Climate Change (IPCC)…
Methane Emissions Hit Record Breaking Levels
Methane Emissions Hit Record Breaking Levels
by Josie Garthwaite
Global emissions of methane have reached the highest levels on record, research shows.
kelp forrest 7 12
How The Forests Of The World’s Oceans Contribute To Alleviating The Climate Crisis
by Emma Bryce
Researchers are looking to kelp for help storing carbon dioxide far beneath the surface of the sea.

LATEST ARTICLES

God Intended It As A Disposable Planet: Meet The Us Pastor Preaching Climate Change Denial
God Intended It As A Disposable Planet: Meet The Us Pastor Preaching Climate Change Denial
by Paul Braterman
Every so often you come across a piece of writing so extraordinary that you cannot help but share it. One such piece is…
Drought And Heat Together Menace American West
Drought And Heat Together Menace American West
by Tim Radford
Climate change really is a burning issue. Simultaneous drought and heat are increasingly likely for more of the…
China Just Stunned The World With Its Step-up On Climate Action
China Just Stunned The World With Its Step-up On Climate Action
by Hao Tan
China’s President Xi Jinping surprised the global community recently by committing his country to net-zero emissions by…
How Do Climate Change, Migration And A Deadly Disease In Sheep Alter Our Understanding Of Pandemics?
How Do Climate Change, Migration And A Deadly Disease In Sheep Alter Our Understanding Of Pandemics?
by Super User
A new framework for pathogen evolution exposes a world much more vulnerable to disease outbreaks than we previously…
Climate Heat Melts Arctic Snows And Dries Forests
What Lies Ahead For The Youth Climate Movement
by David Tindall
Students around the world returned to the streets in late September for a global day of climate action for the first…
Historic Amazon Rainforest Fires Threaten Climate And Raise Risk Of New Diseases
Historic Amazon Rainforest Fires Threaten Climate And Raise Risk Of New Diseases
by Kerry William Bowman
The fires in the Amazon region in 2019 were unprecedented in their destruction. Thousands of fires had burned more than…
Climate heat melts Arctic snows and dries forests
Climate Heat Melts Arctic Snows And Dries Forests
by Tim Radford
Fires now blaze under Arctic snows, where once even the wettest rainforests burned. Climate change delivers unlikely…
Marine Heat Waves Are Becoming More Common And Intense
Marine Heat Waves Are Becoming More Common And Intense
by Jen Monnier, Enisa
Improved “weather forecasts” for oceans hold hope for reducing devastation to fisheries and ecosystems around the world