economic growth and climate change - real GDP tipping point plotted against time.

Our on-going ‘business-as-usual’ CO2 emissions will collapse the global economy by mid century – we must reduce them much faster or we’ll become ‘boiled frogs’

Posted on Posted in Chairman’s Blog

Boiled frog syndrome is when you think nothing much is wrong until suddenly you realise it’s too late and you have run out of time to prevent catastrophe.

The boiled frog fable imagines that a frog dropped into boiling water will jump out immediately. However, if the frog is immersed in tepid water that is then slowly heated, the frog gets used to the gradually increasing heat before realizing – too late – that it cannot escape being boiled alive.

How did this metaphor for our present day attitude to climate change come about?

Climate change science is tough to understand and to explain, so let’s tell the story incrementally, step-by-step, with pictures. Our narrative is based on CO2 emissions, using PAL-1Y, the simplified carbon pricing formula postulated by my colleague Richard Clarke in his book Predicting The Price Of Carbon.

Clarke begins with a simple model to predict the expected loss and damage from climate change and its impact on GDP1. Plotted in Fig. 1 below, the x-axis is the period, from 1800 to 2100. The y-axis shows normalised scaled variables as listed in the key, which are progressively added in, mostly as curves, as the story unfolds.

 

economic growth and climate change - Temperature anomaly plotted against time.

Fig. 1 Temperature anomaly plotted against time.

First, as shown in Fig. 1, the temperature anomaly data from NOAA (National Oceanic and Atmospheric Administration) is plotted. The warming started in the 1960s and has been fairly linear since 1970 at around 0.17Kelvin/decade. Temperature anomaly (Ta in Fig. 1) compares the average temperature on land and sea with pre-industrial values. At present, in 2018, the figure is about 0.85°C.

 

economic growth and climate change - carbon dioxide emissions plotted against time

Fig. 2 Added in are carbon dioxide emissions plotted against time.

Next, as shown in Fig. 2, comes the business-as-usual CO2 emissions curve data which is similar to that of Shell’s projection to 2100.

 

economic growth and climate change - theoretical GDP plotted against time.

Fig. 3 Added in is the theoretical GDP plotted against time.

A theoretical GDP curve is then superimposed, in Fig. 3. Clarke postulates that the true growth rate is about 3.6% per annum net of inflation/currency effects. Over the long run GDP has in practice been about 3%. The degrading of GDP by 0.6% per annum reflects the effects of loss and damage attributable to manmade climate change.

 

economic growth and climate change - real GDP plotted against time.

Fig. 4 Added in is the real GDP plotted against time.

As shown in Fig. 4, real GDP starts to depart from the theoretical values quite soon – around 2020 – and growth progressively slows thereafter. The single black dot in 2100 forebodes what happens next…

 

economic growth and climate change - real GDP tipping point plotted against time.

Fig. 5 Added in is the real GDP tipping point plotted against time.

With just a nudge, the tipping point, shown in Fig. 5, arrives. Here Clarke postulates a tiny weakening of the global economy – of just 0.5% GDP – between now and 2100. The result? The global economy collapses soon after 2070! By the middle of the century nothing short of a miracle could prevent a catastrophe.

 

economic growth and climate change - expected temperature anomaly plotted against time.

Fig. 6 Added in is the expected temperature anomaly plotted against time.

Now the expected temperature anomaly (Ta) is added to the picture as shown in Fig. 6. Note that in the PAL-1Y model Ta falls towards zero as we go back in time but does not go negative. With business-as-usual emissions Ta shoots to well over 4°C, so all the world’s ice will melt.

So what can be done to save us, the planet’s inhabitants, from becoming ‘boiled frogs’?

 

economic growth and climate change - real GDP with emissions stabilized at 40 giga-tonnes per year plotted against time.

Fig. 7 Added in is the real GDP with emissions stabilized at 40 giga-tonnes per year plotted against time.

As shown here in Fig. 7, if world emissions could be stabilized, at say 40 giga-tonnes per year, it’s just possible that the global economy could be saved from obliteration but the risks of such a strategy are too great. Everything we learn about ice melting shows how little we understand it and, unfortunately for us, the reality is normally worse than the climate scientists predict.

Note that this simple model makes no explicit allowance for ice melting and sea level rise. Hundreds of millions of people in coastal cities are already under threat from sea level rise and sinking cities (due to groundwater extraction). And if 40 giga-tonnes of CO2 per year is emitted then temperature anomaly will just keep rising.

That’s parboiled frog syndrome at best, merely delaying the inevitable, and making it far worse for our descendants.

 

economic growth and climate change - The probable ‘best-we-can-hope-for’ scenario for all the variables plotted against time.

Fig. 8 The probable ‘best-we-can-hope-for’ scenario for all the variables plotted against time.

The only plausible strategy is to adhere to the 2015 COP21 Paris Agreement as best we can, and our concluding picture in Fig. 8 plots the resulting emissions in a way judged by Clarke to be ‘realistic’. Whilst still not good enough, he concludes, on this basis, the global economy could stagger on, despite the inevitable, huge, cumulative effect of weather-related economic disruptions and losses.

Add in a toxic blend of the effects on biodiversity, ‘water wars’ from drought-generated conflicts, plastic waste and scarcity of other resources and it’s a no-brainer:

Unless we start adapting our cities and fixing our emissions today, we and our descendants will become ‘boiled frogs’!

 

Bruce Menzies, Chairman, Predict Ability Ltd (PAL)

© Copyright Predict Ability Ltd 2018. All rights reserved.

 

1 Based on the model described in Chapter 8 of Predicting the Price of Carbon.

Bruce Menzies

Author: Bruce Menzies

Bruce Menzies is Chairman and co-founder of PAL. He founded Global Digital Systems Ltd that won the Queen’s Award For Enterprise 2011. Bruce is co-author of six books on geotechnics and geology, one of which won the British Geotechnical Association Prize 2002. He holds doctorates from the Universities of London and Auckland, and is a Fellow of the Institution of Civil Engineers.

Our on-going ‘business-as-usual’ CO2 emissions will collapse the global economy by mid century – we must reduce them much faster or we’ll become ‘boiled frogs’ was last modified: October 22nd, 2018 by Bruce Menzies

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