August 11, 2018, by Brigitte Nerlich

Groundhog day in the hothouse

On 6 August Will Steffen and others published a paper entitled “Trajectories of the Earth System in the Anthropocene”. The paper explores “the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a ‘Hothouse Earth’ pathway even as human emissions are reduced”. This caused some stir, summarised to some extent by Ken Rice here.

Hothouse language

In a piece for The Conversation Richard Betts wrote: “Personally, I found this an interesting and important think piece that was well worth reading. But since this is not actually new research, why is it getting so much coverage? I suspect that one reason is the use of the vivid ‘Hothouse Earth’ term at a time when everyone’s talking about heatwaves. Another is that it’s clearly a dramatic narrative, and not surprisingly this has led to some sensationalist articles.”

This prompted Alice Bell to ask some questions about language! She tweeted “In his Conversation piece, Richard implies that the term ‘hothouse earth’ isn’t exactly a scientific contribution, more a comms one. And that’s a fair enough view. Still, not sure I agree.” She added: “terms like ‘Hothouse earth’ come from science and are woven into how the world works with that science, so maybe we’re better off admitting it’s part of our biz and working from that?”. Exactly, I thought. As I have written about the ‘greenhouse effect’ and the ‘carbon footprint’ metaphors before, I became curious about ‘hothouse earth’ and where that metaphor came from and when it was first used.

Tracing the hothouse earth metaphor

In his column ‘word of the week’, Steven Poole rightly points out that the term ‘greenhouse effect’ was coined in 1907 and continues: “a ‘hothouse’ sounds far more intense. From the 16th century, a hothouse was a bathhouse or a brothel, or a heated room for drying linen, and then a heated greenhouse for cultivating exotic species, metaphorically extended to an environment in which anything (including minds) grows very quickly. Its products are often said to be highly delicate, if not sickly. We are already wilting like hothouse flowers this summer, and there might be no way to smash the glass.” He doesn’t say when the metaphor ‘hothouse earth’ was coined. We’ll come back to that.

For most gardeners a hothouse basically means a heated greenhouse in which plants that need protection from cold weather are grown. That doesn’t sound so bad. The metaphor ‘hothouse earth’, however, focused away from the protection and onto the dangers of destruction from overheating, as highlighted by Poole.

This seems to be related to a scientific/geological definition I found on Wikipedia linked to a distinction between greenhouse/hothouse and icehouse earth: A “’greenhouse Earth’ or ‘hothouse Earth’ is a period in which there are no continental glaciers whatsoever on the planet, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high, and sea surface temperatures (SSTs) range from 28 °C (82.4 °F) in the tropics to 0 °C (32 °F) in the polar regions.” This meaning seems to have appeared at the end of the 1990s in the geological literature.

Hothouse earth in the media

However, I wondered when this metaphor was first used publicly and for a quick forage I looked at Lexis Nexis. I found that it was first used well before the 1990s in 1975 in a brief report in the New York Times. I quote it in full, as it is quite interesting. Hot or heat seems to refer here to ‘heat’ as such, not carbon dioxide emissions (the abbreviations and typos in the article are not mine).

“Dr Howard A Wilcox, in bk ‘Hothouse Earth,’ says man’s output of heat into atmosphere, if allowed to continue to increase at present energy and indus growth rates, will raise earth’s temperature enough to melt polar ice caps and flood many populous areas of earch in next 80-180 yrs; man current puts heat into atmosphere at about 1/10,000 rate at which sun is contibuting heat to earth (5,000-billion-billion BTU’s annually); Wilcox says that present growth rate of energy consumption (4-6% a yr) will result in 80 yrs in mankind’s returning to atmosphere approximately 1/100 of total amount of energy transmitted by sun, raising worldwide temperature 1-3 degrees; even 1-degree rise, through a falling-dominoe kind of reaction, could melt ice caps; Dr William W Kellogg of Natl Center for Atmosphere Research doubts energy consumption will continue to grow at exponential rate; Dr J Murray Mitchell Jr of NOAA see more immediate danger in increasing amounts of carbon dioxide that are thrown off into atmosphere along with heat (M)”

The domino effect metaphor returned this year alongside tipping points after the publication of the recent hothouse article. (On tipping points in the media, see here)

After 1975, 37 news items used the metaphor ‘hothouse earth’, with a tiny peak in 1990 when eight articles appeared. This is as nothing compared to the 276 articles that were published between 6 and 10 August 2018.

Groundhog Day in the hothouse

The little peak in 1990 was prompted by a book written by John Gribbin and entitled Hothouse Earth: The greenhouse effect and Gaia. When looking a the coverage of that book in the news, I was surprised yet again to find that even then the SAME OLD issues dogged climate change as now.

One reviewer, Keith Spoeneman, for the St. Louis Post-Dispatch (Missouri) (13 May, 199) noted: “That the average global temperature will likely rise by some 5 degrees Fahrenheit over the next 40 years, and that the oceans will rise 1 or 2 or possibly more feet in this same period, should come as no surprise to anyone with an awareness of the many scientific warnings that have been voiced on this subject since the unprecedentedly warm decade of the 1980s. But controversy and a powerful inertia have always dogged these warnings.  Every few months, it seems, some new objection is raised, and almost regardless of the scientific response, the political response is a continued wavering and an ever-renewed call for more study of the ‘problem.’”

Solutions to ‘the problem’ were already discussed in the 1975 hothouse earth book by Wilcox, who points out: “Immediate development of solar energy technology to produce solar energy cells, windmills, and ocean turbines combined with open-ocean farming are steps that can be taken to avoid a thermal catastrophe.” Back to, or rather forward again to, 1990.

Another reviewer of the Gribbin book, William Goulding (The Sunday Times, 28 January, 1990), quotes the late climate scientist and climate science communicator Stephen Schneider as saying: “scientific predictions are like ‘trying to gaze into a dirty crystal ball. By taking time to clean the glass you can get a better picture; but at some point it is necessary to decide that the picture is good enough to alert policy makers and the general public to the hazards ahead. That point has certainly been reached with studies of the greenhouse effect and the prospect of rising sea levels in particular.’’” Unfortunately, that point seems to be forever receding into the future…

Maintaining a Goldilocks house

I won’t analyse the mass of articles that have been published in 2018 following the recent use of the hothouse earth metaphor. I just want to say: The earth is our ‘house’. It can be an ‘icehouse’; it can be a ‘greenhouse’; it can be a ‘hothouse’. At the moment we live in a still relatively nice greenhouse of which Goldilocks would be proud, but a greenhouse that’s gradually overheating if we don’t do something about our own foolish actions that led to the greenhouse overheating in the first place.

That’s basically what the Will Steffen et al. paper tried to say, I think. It should be stressed though that the authors wanted to point out a “risk that needs studying, not something that is certain to happen” (New Scientist). But we better make certain that we do both, study what’s going on and deal with the enhanced greenhouse effect that has been our own doing, i.e. reduce emissions.

Image: Pixabay

PS Angela Cassidy has pointed out in as tweet that Brian Aldiss used the metaphor ‘hothouse’ in his scifi novel of the same title, published in 1962! And here is an interview with him about the novel and about climate change!

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