There Are No Time-travelling Climatologists: Why We Use Climate Models

There Are No Time-travelling Climatologists: Why We Use Climate Models Improvements in newer climate models have resulted in larger uncertainties in future climate projections. Are climate models flawed and getting worse? NASA Goddard Space Flight Center

The first climate models were built on fundamental laws of physics and chemistry and designed to study the climate system. Now, the use of climate models is heated ground in the public discussion of our changing climate.

Climate models represent the physical world using a series of equations based on these known physical laws. These models are virtual laboratories; these are the tools that allow us to perform experiments that we can’t conduct in the real world.

Like any scientific equipment, climate models are carefully developed and checked. We base our confidence in a model on its ability to reproduce the current climate and observed changes and also key time periods of the past.

Getting it right

Climate models reliably capture many aspects of our climate system. Models reproduce many important natural climate processes, including the seasonal and daily temperature cycles that we experience in the real world.

Climate models also accurately respond to disturbances external to the climate system itself. In 1992 NASA scientists used the Mt Pinatubo volcanic eruption as a test for their model. They accurately predicted the observed climate cooling that played out in the real world in the early 1990s in response to these volcanic aerosols.

There Are No Time-travelling Climatologists: Why We Use Climate Models Comparison of predicted climate model response to Mt Pinatubo volcanic eruption and observed cooling. Modified from The Mount Pinatubo Eruption: Effects on the Atmosphere and Climate (1996)

Models also capture the observed 20th century warming in global temperatures in response to increasing greenhouse gases. In fact, scientists made accurate climate model predictions of global-scale warming as early as 1975, even before strong warming became evident in observational records.

There Are No Time-travelling Climatologists: Why We Use Climate Models Climate model predictions made in 1975, compared to observations. Modified from Skeptical Science (www.skepticalscience.com/lessons-from-past-climate-predictions-broecker.html)

Experimenting in the virtual world

These virtual laboratories also help us understand the nature of interactions between the interconnected components of the earth. We can see how changes in the land surface from deforestation and agriculture have significant effects on the climate.

We can also examine the response of the climate system to large disturbances, or “forcings”. Previous studies show that large-scale disruptions can occur in the ocean currents and air temperatures in response to idealised ice sheet melting in the North Atlantic.

Models also allow us to investigate future changes. Models project a substantial warming in temperature extremes over the next century, which helps us to assess the potential for future impacts on vulnerable systems.

Looking at the big picture

Despite these modelling successes, we can never perfectly describe our complex, chaotic physical world with a series of equations. Small changes can affect the climate system in complicated ways and we are still developing our theoretical understanding of the most complex aspects of the climate system.

For example, accurately modelling clouds remains a challenge. We don’t know exactly how clouds form, which means we don’t necessarily know how best to represent cloud processes in a climate model. The necessary approximations we make in modelling cloud formation can led to differences between models and the real world, such as too much persistent drizzle in the models.

Our confidence in model results is closely linked to spatial and temporal scales. For global-scale models, more robust results are obtained investigating longer-term, broader-scale changes, than at particular locations, at particular times.

For all these studies, there is no single best climate model but a collection of models to use together. Meanwhile, we have one in a single set of available observations of the real world climate, with all its inherent chaotic variability. To account for this chaotic element, we assess how the average and the range of a group of models compares to observations.

When we use this approach and we consider large-scale changes over decades or more, climate models are powerful tools that allow us to address questions about past, present and future climatic change.

The state-of-the-art

The IPCC’s fifth assessment report is due soon and includes evaluations of the latest generation of climate models. It seems counter-intuitive, but early results suggest that significant model improvements may have resulted in wider, rather than smaller, uncertainties in future climate projections.

Remaining uncertainties do not indicate the models are getting worse or that our understanding of climate change is becoming less clear. In fact, climate models have improved in simulating much of the observed climate.

These future uncertainties partly derive from the newer models now incorporating a greater range of important but complex processes. For example, models may now include small particles of industrial pollution and interactions between the climate, vegetation and the land-surface.

We can liken the development of climate models to natural selection. Successful models and their components thrive, while less effective ones eventually drop off and become extinct.

Scientific, not political, tools

Despite recent improvements, climate models have become a lightning rod of contention. Models are increasingly politicised and model-based studies often elicit heated responses that climate models are flawed and cannot be trusted.

These expectations of model perfection are misplaced; while model certainty is never attainable, we are confident in our use of climate models.

Meteorologists Knutson and Tuleya note that “if we had observations of the future, we obviously would trust them more than models, but unfortunately observations of the future are not available at this time”.

In the absence of time-travelling climatologists, models are unrivalled tools for understanding our changing climate system. That is, climate models are scientific tools. We should recognise them as such and consider them with rigorous scientific, not political, scepticism. The Conversation

About The Author

Sophie Lewis, Postdoctoral Research Fellow, University of Melbourne and Sarah Perkins-Kirkpatrick, Post Doctoral Research Fellow, UNSW

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