Tropical ... but no paradise

Environmental crisis is real

We cannot prevent climate disaster by denying the existence of the problem, argues Daniel Harvey

In last week’s Weekly Worker David Douglass took issue with my letter on climate change (November 1) and presented a whole array of claims, which unfortunately are typical of those that deny the reality of global warming (Letters, November 8). Often this means the issues are obfuscated in a cloud of cherry-picked data points and misrepresented findings, by confusing and conflating different elements in the climate system. Climate changes cannot just be dismissed as things that come and go. They have concrete causes and serious effects on the biosphere - and now on human society as well.

Untangling this can be time-consuming, which is exactly why this confusion on the basics of climate change is promoted by the fossil fuel industry and its lobbies. It is only necessary to point out that the overwhelming consensus of climate scientists is that the Earth is warming because of the increasing concentrations of carbon dioxide (CO2) and other greenhouse gases in the atmosphere. The disagreement within the scientific community on this now, if there is one, is between the majority, who have been saying for 40 years that we need to take immediate action to cut greenhouse gas emissions, and a minority, which says it might be too late, as feedback mechanisms take the matter out of human hands altogether.

Over the last 500 million years, Earth’s climate has varied greatly. As comrade David points out, in the past - in fact, for the majority of this time - the climate was hotter, much hotter, than today. Except for a couple of interruptions, throughout most of the Mesozoic era global mean temperatures were at a stable and balmy 22˚. The concentration of CO2 in the atmosphere was about 1,700-1,900 parts per million (ppm), or six or seven times pre-industrial levels. The Antarctic may have been a “tropical paradise”, as David says, or just ice-free, but the interiors of the large continents were also baked with so much heat that they were very hostile places to most life. Warm-blooded mammals did not fare well in this environment, and were largely limited to nocturnal rodents.

Toward the end of the Cretaceous period, and after, the high levels of CO2 were sequestered into the ground as dead vegetation, which has been compacted under earth and rock and become coal, oil and gas. Since the start of the industrial revolution, capitalists seized on this as a source of cheap energy and, like kids in the proverbial candy shop, have been raiding it, digging it up and burning it - returning it to the atmosphere. The use of fossil fuels was a locus in capitalists’ competition with each other, as well as their perennial struggle against workers. Coal was instrumental in the process of concentrating labour in large cities, where it was possible to maximise the advantage of capital against labour in the competition for work. In the present, the capitalist economy is totally dependent on fossil fuels, emitting 42 billion metric tons annually of CO2 equivalent, including emissions of much more powerful gases like methane and nitrous oxide.

In the last 800,000 years - the time scientists can measure most accurately, using ice core samples - it is true that climate has oscillated in very regular intervals. This means that temperatures have gone up and down between glacial and interglacial periods, over periods of tens of thousands of years. Atmospheric CO2, which closely tracks temperature, has moved gently up and down between 180 and 280ppm. These are the changes which can be tracked back to the things David mentions: solar activity, the wobble in the Earth’s orbit, and its changing axial tilt. They have nothing to do with the dramatic loss of sea ice in the Arctic observed since 1979 or the increases in global temperature since the start of industrialisation. If you plot the changes over the last several hundred thousand years, then they show something like a very natural heartbeat, but if you include the last two centuries, it is more like the patient going into cardiac arrest.

Some of the greatest mass extinction events in Earth’s history are linked to rapid warming. When the climate shifts from a cool setting to a ‘hothouse’, most animals and vegetation do not have the time to adapt. This was true of the Permian mass extinction, where temperatures increased by about 8˚ over the course of about 60,000 years. It is thought this involved large releases of carbon from a protracted period of volcanism. Over the millennia, oceans increased in temperature and acidity, causing about 96% of marine life to die out. The oceans then became anoxic, releasing hydrogen sulphide over the land, as well as deposits of methane from clathrates on the sea floor, causing a second burst of warming. In some areas biodiversity took about 10 million years to recover.

But the carbon release and heating from burning fossil fuels may be taking place about 300 times faster in practice. One of the leading climate models shows that we could get most of the way to similar temperature rises - 5.9˚ by 2100, with a 93% chance of being above 4˚ - if emissions remain on their current trajectory. Confusing this with the regular and gradual changes of the recent geologic past is almost like confusing Jurassic Park with a petting zoo.


Now we can measure the real world effects of global warming. In a paper in Nature by Dr Ken Caldeira and Dr Patrick Brown, it was shown that the climate models predicting the most warming were the best at simulating past real weather patterns.1 In terms of emissions we are still on the Intergovernmental Panel on Climate Change’s ‘business as usual’ Representation Concentration Pathway of 8.5 watts per square metre (RCP 8.5).

And we may be deeper into this crisis than we think. Through the burning of fossil fuels, use of low-quality coal and aviation emissions, we have been masking the effects of surface warming through the emission of sulphates that reflect solar radiation back into space. A paper by James Hansen et al in 2011 shows this aerosol masking may be hiding up to half of the temperature increase so far.2 The burst in warming in the northern hemisphere and Arctic circle has coincided with a lot of measures taken in developed countries since the 1970s to cut some of this particulate pollution out of the atmosphere. When they are removed entirely, as was pointed out in the paper, “the Faustian payment will come due”.

The CO2 concentrations in the atmosphere today are at 407ppm. In the mid-Pliocene period three million years ago, atmospheric CO2 levels were similar to today, and temperatures were 2-3˚ higher than the pre-industrial level. Within a matter of a few decades CO2 may be between 550 and 600ppm. So we are rapidly moving out of the stable equilibrium to which humans and most animal and plant life are acclimatised. The transition to agriculture for humans was only possible because of this stable environment.

At the same time, there seems to be a domino effect in the environment, as interlocking parts of the climate system break down. According to the recent survey by the World Wide Fund for Nature (WWF), involving 59 leading scientists, we have already lost 60% of the population of vertebrate animals since 1970.3 Even insect declines in the order of 75% have been recorded in some places. Plankton in the oceans has fallen by 40% since 1950, and we are seeing the spread of oceanic ‘dead zones’. The Amazon rainforest has experienced three ‘once in a century’ droughts - in 2005, 2010 and 2015-16 - as well as ‘ordinary’ droughts in 2007 and 2012.

The problem with taking a blasé attitude to climate change is that we live in a world of seven billion people - soon to be eight or nine billion. Between now and 2040, it is believed that we will need to produce 50% more food to accommodate this, as well as the changing diets in middle-income countries. This will mean increasing production from an already overstretched food system. We will have to do it in a much more unpredictable climate, with extended droughts, changing precipitation patterns, declining aquifers, widespread desertification, salt-water intrusion of land in coastal areas, and a rapid drop in the numbers of pollinating insects. A widely reported study of these effects by a team at Anglia Ruskin University showed a breakdown of the food system was likely, unless serious remedial action was taken.4

With a massive technological effort, it may well be possible, as David says, to overcome this level of crisis, but it may not be possible to adapt to a full-blown ‘sixth mass extinction event’ that is indicated beyond this in the models. It is also becoming clear that the capitalist ‘solution’ to such a mass extinction event is predicated on the assumption that the victims - primarily the world’s poor at first - are expendable. As Jared Diamond has elucidated, the collapse of complex societies is often a result of wealthy elites feeling they can insulate themselves from the effects of their decision-making.5

Such an environmental crisis is intrinsically linked to capitalism - which makes the need to supersede the current profit-based system in favour of production for need more critical than ever.


1. www.nature.com/articles/nature24672.

2. https://pubs.giss.nasa.gov/abs/ha06510a.html.

3. https://c402277.ssl.cf1.rackcdn.com/publications/1187/files/original/LPR2018_Full_Report_Spreads.pdf?1540487589.

4. www.anglia.ac.uk/news/report-shows-vulnerability-of-global-food-system.

5. www.ted.com/talks/jared_diamond_on_why_societies_collapse.