Unnatural Climates

  • Written by  Chris Caseldine
  • Published in Opinions
Unnatural Climates ahupepo
08 Jul
2016
Whether anthropogenic climate change began over 8,000 years ago or within the last few centuries, our inadvertent experiment in climate geoengineering is now not only discernible in its effects, but is also providing major challenges for ourselves and future generations

Whatever action we take, from managing greenhouse gas emissions to active solar radiation management, it will have climate consequences. It’s therefore appropriate to ask two fundamental questions related to climate as a context for current and future actions: 1. What is or would be ‘natural’ climate, without human interference? 2. What sort of climate is the objective of intervention by whatever chosen method?

Establishing the character of ‘natural’ climate is made difficult by our potential influence over the Holocene, especially if we have indeed had a long Anthropocene with human changes in greenhouse gas emissions over several millennia. However, from our study of the Holocene and earlier interglacial climates it is possible to infer the climatic results of the continuing interplay between the changing astronomical position of the Earth, solar irradiance variations and episodic volcanic activity.

By running these natural variations forward in time we can project a future pattern of climate variations over future decades, centuries and millennia assuming we were not here. This is, of course, of little value for our immediate concerns but provides a context for current debates – there is for instance the possibility that we may have been heading close to a tipping point for Ice Age inception prior to greenhouse gas use, and given the impact of CHCs and their like we now have the technology to offset any future glacial threat.

Defining ‘natural’ climate is however tricky in deciding what criteria to use. Over a millennial time scale it is probably best to consider GHG concentrations as they best define previous glacial/interglacial changes; any drop below ca. 270ppm CO2 would be likely to take us out of an interglacial. As we head into concentrations well in excess of those experienced for several millions of years, a ‘natural’ climate seems a long way off.

Climate stability is a difficult concept to define, and even more difficult to achieve

Mean temperatures at various spatial scales provide another approach using the Holocene as a template, the range of temperatures providing a ‘natural’ envelope. This has the advantage that it accords with the messages coming from the IPCC and other bodies of a need to restrict temperatures to no more than 1.5°C as in the Paris agreement.

Increasingly though messages are couched in terms of avoiding dangerous climate change and the need to return to some stable climate state. The Holocene is seen as a period of stable climate, lacking abrupt change and periods of climate getting out of control. Climate stability is, however, a difficult concept to define, and even more difficult to achieve. While it is likely that a loss of Polar ice would lead to potentially unstable global climate, there is a danger in assuming that without us global climate was rather akin to the Garden of Eden and somehow ‘safe’. We need to recognise the still uncertain and variable climate that occurs with or without human activity.

The difficulty of deciding how to define ‘natural’ climate means that when we examine the objectives of organisations and individuals in terms of climate it is not surprising that they are expressed in varying ways. Whether expressed in terms of greenhouse gas emissions or global temperatures, or as climate we do not want to experience, the objectives can appear vague. As the various sides of the climate debate become more entrenched, the terminology inevitably mirrors this, with the idea of there being a climate solution for instance, implying that if only we do A or B climate will return to ‘natural’ and hence be a beneficial and well-behaved part of the Earth system.

‘Natural’ climate is not benign; from a human perspective the climate of the Holocene within which civilisations developed has been one that human societies have coped with and at times benefited from. It has also been a period when extreme climate events have affected, and continue to influence the way we live. To anyone suffering droughts, hurricanes or floods, climate is still a problem and it is here that the promises of climate geoengineers add a further complication. Climate geoengineering, especially the quick fix of solar radiation management, offers a way to offset greenhouse gas influences and manage (stabilise?) climate. If it were used and successfully limited warming without any of the perceived associated risks, then important ethical questions would remain. Extreme climate events are part of our Holocene climate experience and can have devastating impacts on human societies. Once we manage our climate to keep it as ‘natural’ as possible, however defined, then why should we not use such interventions to make life easier for those suffering from climate disasters? ‘Natural’ climate comes with many risks for humans, it is not a perfect world.

Chris Caseldine is Emeritus Professor at the Centre for Geography, Environment and Society at the University of Exeter

This was published in the July 2016 edition of Geographical magazine.

Share this story...

Submit to FacebookSubmit to Google PlusSubmit to Twitter

Related items

Leave a comment

ONLY registered members can leave comments and each comment is held pending authorisation before publishing. Please login or register to voice your opinion.

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

LATEST OPINIONS

Subscribe Today

EDUCATION PARTNERS

Aberystwyth UniversityUniversity of GreenwichThe University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • REDD+ or Dead?
    The UN-backed REDD+ (Reducing Emissions from Deforestation and Forest Degradation) scheme, under which developing nations would be paid not to cut dow...
    The true cost of meat
    As one of the world’s biggest methane emitters, the meat industry has a lot more to concern itself with than merely dietary issues ...
    Long live the King
    It is barely half a century since the Born Free story caused the world to re-evaluate humanity’s relationship with lions. A few brief decades later,...
    London: a walk in the park
    In the 2016 London Mayoral election, the city’s natural environment was high on the agenda. Geographical asks: does the capital has a green future, ...
    The Money Trail
    Remittance payments are a fundamental, yet often overlooked, part of the global economy. But the impact on nations receiving the money isn’t just a ...

MORE DOSSIERS

NEVER MISS A STORY - follow Geographical

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in OPINIONS...

Opinions

2017 is the Chinese year of the chicken. This year, the…

Opinions

Despite the many claims of authenticity, modern filmmaking is still…

Opinions

With medical (and especially dental) tourism on the rise, Vitali…

Opinions

More drugs than you might think are derived from, or…

Opinions

The growth of cities is one of the defining challenges…

Opinions

On a long-awaited return to Ukraine, Vitali Vitaliev finds a…

Opinions

The world is changing, but one thing stays the same…

Opinions

We live in an age where awe and wonder at the…

Opinions

$150million. That is the estimated black market value of the…

Opinions

How many other species do we share our planet with?…

Opinions

Geography – both physical and human – can help people…

Opinions

Whether anthropogenic climate change began over 8,000 years ago or within…

Opinions

Could artificial dams, placed at the heads of glaciers be…

Opinions

What does a life outside the European Union mean for…

Opinions

Rewilding needs to be positioned as a forward looking and…

Opinions

The UK has a two-track system of support that distinguishes…

Opinions

Peace rarely makes the headlines, meanwhile accounts of violence prove…

Opinions

Why not use the intellectual capital that is growing so…

Opinions

The infamous Pacific garbage patch is only a small fraction…

Opinions

We need to starting thinking much more about fungus and…