Monthly Archives: March 2018


The human species is hard to define biologically, except perhaps as a great ape marked out by hairlessness, bipedalism, and linguistic, technological and cultural creativity.  The problem is that our inheritance is muddled, with signs in our DNA, bodies and behaviour that join us to all the other apes – gibbons, chimpanzees, orangutans, gorillas – as well as to Denisovan, Neanderthal, Modern and other lineages.  Our various human-like ancestors certainly competed wherever they overlapped in time and space, in every way from ecological friction to voluntary and forced inter-breeding, and genocidal conquest, leading to a few winners and a lot of mixtures.  Meanwhile, they also engaged over the last million or so years in waves of long-distance colonisation, all the way from Africa to Australia and the Americas.  We are more sensitive to differences than similarities, so it can come as a shock that there is only one species of modern humans, but this is what our deep history has produced.  So our job is to accept our biological unity while respecting cultural differences and the influence of our varied societies, from which we derive most of our habits, assumptions, priorities, and thoughts.

People are the most common large mammals that have ever existed, our recipe for success being strong adaptive capacity among groups of cooperating individuals in competition with other groups.  We consistently invented, tested and demonstrated to others, through dialogue, trade or conquest, the power of new technologies (such as weapons) and new ways to manipulate each other (such as blarney) and the environment (such as farming).  The result is that our collective ecological influence built up through the Holocene era (the 11,700 years since the last Ice Age), until we induced what is known as the Holocene-Anthropocene Transition or HAT.  So a new Anthropocene era (‘the Age of People’) is counted from the 1st of January 1950, at the mid-point of the HAT.  It features climatic instability, sea-level change, ecological collapse, the mass extinction of non-human species, and the ubiquity of plastic, nuclear and industrial residues, all of which will show up clearly in the sedimentary rocks of the future. Impact on this scale is clearly enough to make people among the most important things in the world.

There are, however, other ways to look at importance. Because of how we evolved, as a social species living in competing groups, people are almost always stronger collectively than they are alone.  Thus our key priority is almost always to remain in a successful group, and our feelings of community, friendship and family are almost always vitally important to us.  Each society is then maintained through the indoctrination of all the group’s children into each group’s myths of origin, identity and entitlement, its ways of doing and not doing things, and its ways of thinking and not thinking.  All ideas of justice, evil, merit, leadership, etc. come from this indoctrination.  The inherent conservatism of such a system is mitigated by individuals having occasional flashes of insight, induced by contact with nature, with other people, and/or with mysterious internal or external phenomena.  These flashes then offer an ambiguous way for people to see themselves, and at least potentially for a conscious universe to see them, as very important indeed.

Thus, individuals, groups, relationships, myths, values, and mysterious insights are all important, and all contribute to the collective importance of the human species.  But, it is clear that people also have enough mental flexibility to do new things.  A person may contemplate the common roots of all people, their deep history through hundreds of millennia, their ultimate unity with all living things and with nature herself, and their shared capabilities and personal fates.  The more this is done, the more reasonable it is to treat everyone as you would like to be treated: politely, generously, respectfully, as an equal citizen.  This streak of reasonableness is yet another reason why people are so important, since it can break down social boundaries – of class, caste, race, gender, age, disability – and it can even be extended to non-human species, and to nature. But an assumption of equality like this leads towards fair and sustainable societies, and away from selfish competition.  Now that we’ve bludgeoned the biosphere to the point of collapse, this capacity of people to learn to respect each other and nature has to be the most important thing of all.  The sooner we use it the better.

© Julian Caldecott

Too many people

When Paul Ehrlich published The Population Bomb in 1968, there were 3.5 billion people on Earth, up from 1.4 billion in 1901 and heading for our early-2018 total of 7.6 billion.  Ehrlich feared the worst – accurately predicting, in general terms, the stress that meeting everyone’s needs would place on the living world.  He also proposed some alarming and heavy-handed remedies.  All this has just been been revisited in The Guardian’s over-stretched cities series, in a 50th anniversary interview with Ehrlich.

I once planned a book on population, since I’d noticed that it was a taboo subject yet, to an ecologist, one that simply had to be considered.  So I tried to find out why there was so little on population, which must surely be a starting point for the sustainable development of anyone’s country, or immigration issues, or ecological collapse, mass extinction or climate change.  And yet it wasn’t anything of the sort.  I concluded that this was because it’s all too difficult, far harder than any of the specific development issues since it’s connected to what we do as a species: competitive breeding among peoples, cross-contaminated by issues around patriarchy, family planning, sex education, adoption, immigration, juvenile pregnancies, class, honour killings, religion, euthanasia, test-tube babies, you name it!

Besides, for various reasons that have been perfectly valid for at least 99% of our species’ time on Earth, few people even see that there might be a problem with ‘population’.  Into this mess only the bravest or most foolhardy are likely to venture.  So I chickened out, and here we still are, heading for unimaginable global calamity and taking the whole living world down with us.  What to do?

© Julian Caldecott

Climate change and migration

The World Bank’s publication Groundswell: Preparing for Internal Climate Migration looks at sub-Saharan Africa, South Asia, and Latin America and considers how climate change will force people to move inside their own countries as their livelihoods are undermined.  It concludes that the numbers affected will be in the tens of millions in each region, and that the problem will escalate without “concerted climate and development action”.

I touched on all this in my book Aid Performance and Climate Change, writing that “climate change will inevitably cause the displacement of large numbers of people, from small islands and coastal zones mainly due to sea-level rise, salt intrusion and storm exposure, and within continental systems mainly due to drought and desertification, with flooding, disease, fire, and other hazards adding to the pressures.  Population movements may be involuntary and sudden, or voluntary and slow, but will interact with policies, plans and laws at an increasing rate.  The chaos in Europe resulting from the 2015-2016 mass arrival of desperate people displaced by conflict in south-west Asia draws attention to the need for careful contingency planning and the resourcing of adaptive measures.

“This would apply, for example, to such scenarios as the irreversible flooding of major cities, the creeping emigration of people who abandon life in water-stressed areas, and the failure of entire national economies among small-island developing states and deltaic countries.  The starting point for planning will be different in each case, depending for instance on cultural, geographic, and historical factors (which will affect how easily a group of people can be accommodated in a new setting), and whether a policed national boundary limits the movement of displaced people.  In all cases, while it is tempting to deny the problem and its causes, this response is not viable so coherent and acceptable solutions will need to be prepared for and budgeted.”

There is much here to think about for everyone, everywhere (including Europe).

© Julian Caldecott

Water and life

Water makes life on Earth possible.  It unites the living world like nothing else.  From the lunar tides, ocean currents and seasons to the molecules that build us all, it permits and regulates all life.  Embedded within this big picture, subject to the rules of ecology but often careless of them, are people.  Almost all the world’s water is salty but we live on land, where a regular supply of fresh, clean water is utterly precious. It is the single most important of the ‘on/off’ switches that are hidden under the floorboards of our lives.  But we have allowed these sources of fresh, clean water to be abused, diverted, polluted, or dried up.  Repair is possible, but only by focusing on the ways of nature and the needs of the weak. And now climate change is demolishing the very fabric of our home, making everything worse.

Water has a special structure in which its molecules, each made up of two atoms of hydrogen and one of oxygen, have a different charge on each side, so the molecules attract one another.  This attraction is called a hydrogen bond, and it is strong enough to join water molecules into a swarm that behaves like a supermolecule, but weak enough that the bonds continually form and break depending on how much energy there is in the system.  When there is very little energy, the molecules freeze together into ice; when there is much more, they break apart into steam.  But at middle energies, they ‘shimmer’ in a way that makes life work at the level of cellular structures and chemical metabolism.

Because water molecules are polar – each with a positive and a negative side – they can get a grip on all sorts of other molecules, so water dissolves and mixes with more things than any other liquid.  Then, the hydrogen bonds also do weird things to how water behaves under different conditions, which make life possible at the level of organisms, ecosystems, and the whole biosphere.  They allow water to absorb or lose a lot of energy before it changes from liquid to ice or steam, so blood and ocean currents carry a lot of heat.

Put these things together, multiply them by a couple of billion cubic kilometres of water, each weighing a trillion tonnes, and stir using the energy of a vast thermonuclear reactor (the Sun), and you have the main unifying theme of our living world.  But because of the hydrogen bonds, ice needs 80 times more energy to melt than liquid water does to warm up.  This alone puts water among the most important things right now, since the ice in the Arctic Ocean has been absorbing the extra heat of global warming for decades, and every summer there is less ice up there.  When it finishes melting, only a few years from now, a sudden heating of the Arctic is inevitable, along with a surge of methane and other greenhouse gases. This is what people mean when they talk about ‘tipping points’ and ‘runaway climate change’, and it could spell the end of the only living world that we have ever known.

© Julian Caldecott