Speech by Sir Mark Walport at the Natural History Museum's 2013 annual science lecture.
Sharing the planet, I think, really is humanity’s greatest challenge. It is a challenge for us to share the planet with each other - although that is not primarily what I am going to be talking about tonight - and it is certainly a challenge for some of the other species with which we share the planet.
The diversity of life
This could not be a better place to start with the diversity of life. A short walk around this great building will illustrate the extraordinary diversity of life on this planet.
So Beatrice, newly born, [in the middle], shares the planet with an orchid [top left], an oryx [bottom left], a diatom [bottom right], and [top right] - an organism which she might not be quite so keen to share the planet with - a head louse. Sadly head lice are very common, so she may find it quite hard to get away without sharing her head with a head louse at some time.
Sharing our genome
We share our planet with other species in several ways. Firstly we share the basic mechanisms of life; we share our genomes - the basic constituents of our biochemistry, of our inheritance.
This slide depicts a very large and extensive family tree, which links all of life on earth, from its very beginning 5 billion years ago until the present. You can just about see that there are various periods of extinction. There is a little triangle of white towards the right, which is when the diplodocus - which sits in the centre of this room - disappeared from the planet. The common denominator of all the species on this is nucleic acids.
It is worth pausing for a moment just to recognise the extent to which we do share our genomic sequence, both amongst ourselves and with different species. The person sitting next to you in the audience - assuming they are not a blood relative - will be different from you at about 1 in every 1,000 base pairs. That genetic variation accounts for all of the extraordinary genetic variation between humans.
But of course we are also remarkably similar to other species. The chimpanzee shows only about 2 differences per 100 base pairs between people and chimps - so 98% of the sequence is identical. Even the mouse, which we think of as a rather different mammal, shows only 40 differences per 100 base pairs. Moving back on that evolutionary tree you can see small regions of similarity between people and nematode worms. In fact those small regions of similarity - set out in blue on the slide - actually mark the parts of the genome that really matter, that encode the structural proteins in the nematode and in humans. That genetic sharing is very profound and brings all of the organisms in this museum, alive and dead, together.
Sharing our environment
But we also share our environment. Much of what I am going to talk about over the next few minutes is about the challenges of humans sharing our environment with other species.
Here we have the migration of millions of crabs - between 40 and 45 million - on Christmas Island, where they migrate over land to lay their eggs in the ocean. This of course is where they encounter the obstructions that human beings lay in their way - which in the case of red crabs are managed by road closures. The challenges to other species from human infrastructure can be absolutely extraordinary, and I will explore that a little bit more over the next few minutes.
Generating our atmosphere
If we go back billions of years, I think that we forget at our peril that, our atmosphere - the atmosphere that we use and are able to breath - was substantially generated by living organisms in the first place. Those living organisms generated the oxygen in the atmosphere through photosynthesis and then, after they died, formed the deposits that give us our fossil fuel. Photosynthesis is thought to have begun about 2.5 billion years ago. These cyanobacteria - or blue-green algae - were the first that were thought to evolve the capability to photosynthesise. Then the carboniferous forest - the image of which is from an old diorama displayed in the geological museum as was - were extremely important in generating our atmosphere.
We are familiar with the organisms that breathe air, but the bacteria from many billions of years ago have also left their descendents. We can see some of those around extreme environments. The photograph here is of the Grand Prismatic Spring and the lake around it. The temperature of the water in the spring is at about 70 degrees at the centre. The bacteria that live in there, and which give us these extraordinary beautiful colours, are sometimes known as extremofiles. They are organisms that love extreme conditions. What we have realised increasingly in recent years is that almost everywhere you look on this planet there are micro-organisms living - bacteria, viruses - and they can live under the most extreme conditions.
Inheriting our atmosphere
It was organisms such as these that, billions of years ago, were responsible for generating the atmosphere. On the scale of this graph - the x-axis is 2.5 billion years, so a very long time indeed - what you see is the rise in oxygen concentration. Oxygen has not always been at 20% in our atmosphere, it started billions of years ago at very low concentrations. Organisms such as those bacteria started to photosynthesise and they took up carbon dioxide and metabolised that to oxygen, which was then released into the atmosphere. You can see over 2.5 billion years the concentration of carbon dioxide falling and the concentration of oxygen rising to about the level that it is in the atmosphere today.
Our cousins, our distant ancestors, played an extremely important role in enabling us to live on this planet by generating an atmosphere that we have adapted to and evolved to breathe.
Inheriting our energy
As I have already indicated, not only did they give us the inheritance of our atmosphere, but they also gave us the inheritance of our fossil fuel. Those carboniferous forests turned into deposits of coal. The marine organisms fell to the bottom of the ocean, and gradually under conditions of great heat and pressure, turned into oil. And both of them turned into oil and gas.
Our relationship with other species
Humans have had an important relationship with other species for very many years indeed. These are images, which will be well known to people in the room, from the Lascaux caves in France. They are estimated to be about 17,300 years old. These are extraordinary paintings of animals, of many species which have now gone from Europe.
Moving forward to about 2,500 years ago, humans had a somewhat less attractive relationship with animals. These are Assyrian carvings from Nineveh and the excavations at Nimrud. Here we see King Ashurnashirpal II shooting at an already wounded lion. To some extent we can only guess at how people thought about animals in those days from the images they left behind.
Classifying the world
I want now to move forward to the present time - after the enlightenment. This takes us to the foundation of this museum and the enlightenment at the end of the 17th century, and to a person of extraordinary importance in this museum - Sir Hans Sloane.
He was a physician and a collector who amassed the most extraordinary collection and started to increase our understanding of other species by starting to classify them. Here are some plant specimens from the Carolinas, which are still preserved in the Sloane collection.
Ordering the natural world
From then things have preceded apace. Here is [Carl] Linnaeus - who gave us the binomial classification that we still use today - pursuing the enlightenment, and increasing our understanding of the diversity of the natural world.
It was not long before humans started to cause problems with other species by causing their extinction. The dodo’s lifespan - in terms of human knowledge, or at least European knowledge - really started in 1598 when Dutch sailors first discovered the dodo living in Mauritius. Sadly just over 60 years later they had hunted them to extinction. So it did not take long for humans to start, not only discovering new species, but hunting them to extinction as well.
Discovering the extinct
It was in this room in the 19th century that we started to understand, discover and describe species that had become extinct many thousands of years before. Here is Mary Anning, the great fossil hunter, and one of her fossils of the plesiosaur. And both the painting and the fossil are in this museum.
But taxonomy has moved apace. Moving to DNA sequencing, it is now possible to identify and classify the world at a depth that was not conceivable before. We can use genetic taxonomy to classify species in an extraordinary depth of detail, to divide species that we once thought were the same, and to find out much more about variation within and between species.
This is a bottle of beetles collected by flogging the canopy in Borneo. You can start seeing the sort of taxonomic tree [on the right] that can be developed by using nucleic acid sequencing.
Going back to those extremofiles that I mentioned earlier, it has been possible to discover many micro-organisms that we simply do not know how to culture in the laboratory, just by sequencing them.
Discovering the invisible
As we learned more about the species with which we share the planet, new tools gave us new ways of expanding our knowledge. The microscope of van Leeuwenhoek led to our discovery of an invisible world that could only be seen at great magnification.
Here is Louis Pasteur whose many contributions to biology and society we still celebrate today. He was able to demonstrate the importance of yeast in fermentation. The illustration [top right] shows a classic experiment that Pasteur conducted. He took 2 bunches of grapes and covered one up. He demonstrated that you would get fermentation of the uncovered grape, but the grapes which had been covered, which were protected from the deposition of mould, would not ferment in the formation of wine.
A whole world of microbiology opened up to us during the 19th century and it has continued to give us amazing discoveries to this day.
Sharing our body
We have discovered much more about another type of organism with which we share our world. We tend to think of ourselves as humans on our own, but we each share our own body with trillions of organisms. Although it is slightly distasteful around dinner time - each of us has about 1kg of bacteria in our gut. These are extremely important to us in both health and disease; in affecting the way we absorb food and in helping to form vitamins. And when that flora gets disturbed, it can cause serious illness.
Everywhere you look on our bodies you will find bacteria living.
Other species too have a microbiome that is essential for their health and wellbeing. The rumen of the ruminant enables it to digest otherwise indigestible plants. It is only possible for the yak here to digest grass because of the micro-organisms that it keeps in its rumen - the protazoa, the bacteria - which digest carbohydrates, and themselves generate some of the methane that these organisms emit.
Our deadliest rivals
Of course the microbial world also contains some of our deadliest rivals. Here we see an example of a bacterial infection - the cholera bacillus. One of the greatest advances in human public health was separating the water we drink from the water we excrete. The image of cholera reminds us of the work of that great epidemiologist John Snow, who, working in Soho, did the first proper public health epidemiology by analysing who got cholera and who did not. He recognised that people’s susceptibility to cholera depended on which pump people they took their water from - and of course he famously removed the pump handle.
In the tropics there are many parasites. Here you see a malaria parasite and [on the right], from the viral world, the Influenza A virus.
In terms of our relationship with other species, many of our most deadly infections have been transferred to us from another mammalian species - these are known as zoonotic infections. You can see a series of examples of them on this slide - starting with the Ebola virus, a deadly haemoragic which is thought to have come originally from bats. Here we see E-coli O157, which causes serious diarrheal disease and can cause kidney failure, and comes from cattle and other farm animals. We see the HIV virus which transferred to humans from other primate species. The list goes on. Indeed the Influenza virus occurs in both birds and in pigs, and it is because of the mixing up of the influenza virus genome between those different species that we get new outbreaks and pandemics of influenza.
Our dance with infectious organisms
The way we share around those infections has changed very dramatically in recent years. This is a map of the world which is created entirely by airline routes. Any contours that you see on the countries are drawn by the airline routes, not by the boundaries of the countries themselves. When you see a map like this you realise that the opportunities for humans to move, not only themselves but other species associated with them, has changed in unimaginable ways.
If we now look at the SARS infection, you can see how that moved around the world along the airline routes. The outbreak that occurred a few years ago could be tracked back to an infection in a single person staying in a hotel room in Hong Kong. It then travelled around the world. You can see the routes of all the travellers, and how it ended up in Canada, in America, in Europe, in South America and in Australia.
An infection that might have taken months or years to travel around the world, in an era of airline flight, can move extraordinarily quickly.
Moving species around
One of the important human habits has been to move animals around. We have sometimes done it deliberately, and we have sometimes done it accidentally - with both good and bad consequences.
This includes our foods, the foods that we take for granted. I’ll show you a map in a minute showing how much we have moved them around the world. But equally we have taken organisms such as rats with us and they have caused havoc to other species living around the world.
We have moved animals and plants for many different reasons. We have moved them, in the case of the chicken - which originated as the jungle fowl in Asia - for food. We have moved dogs around - and adapted them, as in the case of this shih tzu, for aesthetic reasons - as pets.
And we have moved them, sometimes with dreadful consequences, in an attempt to control another species. The Cane Toad was moved to control a beetle but, in doing so, we lost control of them, and they themselves became a pest probably as bad as the beetle.
We have moved plants for aesthetic reasons. The Islands of the Azores are made beautiful by hydrangeas that come from the Far East.
Another plant that humans moved to the Azores, the Ginger Lily, is now an extraordinary menace and grows in an uncontrolled fashion. The Japanese Cedar, which was moved for the purposes of timber, has caused great damage to the native species.
The point I am making in this section of my talk is that we have caused the most extraordinary change in our relationship with the natural species just by moving them around - in a sometimes thoughtful, sometimes thoughtless, and almost entirely unregulated way - for many generations. I will leave that thought with you as we progress towards the end of the talk, when I want to talk about some of the technological fixes, and how our attitude to some of the technology appears quite different when we think of it in terms of the willy-nilly way in which we have moved species around in the past.
The rabbit is a very well known example, brought to Australia for food and for their pelts. This [slide] was the consequence; uncontrolled proliferation of rabbits, and eventually the successful use of a biocontrol, by bringing in a virus to which rabbits were susceptible - the myxoma virus.
The globalisation of food crops
This map shows the extent to which we have globalised the foods that we take for granted. Most of us, I think, have forgotten where they started.
From South America;
- tobacco (somewhat less desirable)
From South East Asia;
- sugar cane
From Central Asia;
From Central America;
- dry beans
We have moved over many years - in some cases thousands of years - these plants around the world. And in moving them we have done the most extraordinary genetic engineering through breeding.
Here is the wild mustard plant, which you can see is the originator of a whole series of ‘eat your greens type’ plants. We have:
- kohlrabi - where the stem has been modified
- kale - where the leaves have been modified
- broccoli - where the flower buds and stem have been modified
- brussel sprouts (seasonally appropriate) - where the lateral leaf buds have been modified to grow the sprouts
- cabbage - where the terminal leaf bud has been modified
- cauliflower - where the flower buds have been modified
This has all been very successful, particularly if you think about how far these plants are removed from the original plants by our selective breeding.
We have done the same with many other species. The dog - which was almost certainly originally domesticated for working purposes as herding or hunting dogs - has gone on to have the most extraordinary degree of genetic modification. Looking at the image from the front of ‘Science’, which compares a very large dog and a very small dog; it is actually a mutation in 1 gene called IGF1, a growth factor gene, which is responsible for the difference in size. So, small genetic mutations can have quite big affects in the different varieties of dogs that we now consider as pets.
Humans have shared the planet with other species. We have moved species around the planet, sometimes deliberately, sometimes accidentally. We have modified species, often for good, but sometimes not for good - because if you think of some of those dog strains, many of them are actually extremely unhealthy. But humans have also modified the environment.
Modifying the environment
This slide, which illustrates the last few 100,000 years, shows how humans have moved from;
- using fire
- manipulating stones
- domestication of fruits and animals - approximately 10,000 years ago
- development of cities and the built environment
- pasture and plough appear in the UK - a couple of thousand years ago
- Europe is deforested - a thousand years ago
- invention of the practical steam engine - 100 years ago
Up to today where there is unequivocal evidence that humans are changing the climate of the planet.
It was subsistence farming and the ability to keep animals for agriculture that enabled the extraordinary expansion of humans out of Africa, which is illustrated on this slide.
We have moved from that subsistence farming - that pastoral existence - to a world in which intensive farming has become the norm, and it is extremely important if we are to feed the enormous population on the planet.
And you can see different examples of intensive farming on this slide; not only bringing animals together at very high density, but also using water to bring the desert to life.
Our hunger for resources means that the relationship between humans and other animals is changing yet again. Here you see one of the challenges at the moment; how to control the spreading epidemic of bovine TB, which we know is also present in badgers.
Another topical issue is our competition for food stuffs with other organisms. Here we see a field being sprayed with neonicotinoid pesticides, and [top left] you see the reason that it is being sprayed - the black aphid. What the black aphid does is it sucks the sap from these plants, rendering them susceptible to the fungus which you see in the bottom left.
Part of the challenge of insecticides is that you want them to kill the insects, such as aphids, causing the harm, but you don’t want them to kill the other insects which are pollinators, such as bees. Our human relationship with bees and other pollinating insects is extremely profound; without them, not only would we not have our honey, but much more importantly we would not have many of the plants on which human health depends because they require pollinating insects.
This was a photo that I took a few years ago in Spain. This is the sort of pasture that one hardly ever sees now - you can see the density of the flowering plants. The challenge is how do we maintain that and at the same time feed the planet. We are seeing competition at every level.
This slide will be instantly recognisable as the Aral Sea taken from the air. You can see, starting in 1997 and ending in 2010, the extraordinary way in which the abstraction of water from the Aral Sea has reduced its size and destroyed cities. Moynaq had 30,000 people in the fishing industry, but that is now all gone.
One of the dangers of our modifications to the seas and the oceans is that we can’t easily see what is going on under the surface.
There is a risk of; ‘out of sight, out of mind’. Here we see, [on the right], healthy coral, [top left], coral that has died and been bleached, and [bottom left], coral which has got algal overgrowth associated with fertilizer run-off.
This slide shows the deforestation of Europe that occurred between 1000 BC and 1500 AD. You can see that England and Wales changed from about 90% tree cover to about 17%.
Humans are changing the way we share the plant with other species and the environment in which we all live together.
The pace of change picks up with industrialisation. I realise as I am giving this talk that I am becoming more and more depressed, but I hope we will come to a more positive end.
It is difficult to give this talk without showing the graph that shows the change in human population. This is the world’s population in millions. We have reached about 7 billion people on the planet, and you can see the extraordinary timescale during which that exponential expansion has happened.
And on the next slide you can see what has happened to the atmosphere; the shape of the graph is very similar. The abscissa - the x-axis along the bottom - of this graph is very much longer. In the last graph this went back to 2000 BC, but this graph goes back 800,000 years. What the plot shows is the concentration of carbon dioxide in the atmosphere, in parts per-million, over the last 800,000 years. You can see that before the industrial revolution - which is the very steep rise on the right of the graph - the concentration of carbon dioxide in the atmosphere never really rose above 280 parts per million. But since then - and the blue spot is the observed figure in 2012 - the carbon dioxide concentration has reached about 400 parts per million. The green spot and the yellow spot - are 2 possible scenarios for what we might achieve by 2100; one where we curb our emissions very severely, and the other, what happens if we carry on emitting carbon at the present rate.
Just to put some numbers on that, each year human beings are putting up about 10 gigatonnes of carbon into the atmosphere. What is 10 gigatonnes? 10 gigatonnes is 10 billion tonnes or 10,000 million tonnes of carbon, and each year we are emitting that into the atmosphere.
You can see where that is all coming from on the inset graph [top left]. The emissions start going up in about 1850, and you can see the emissions from coal, oil, gas, and the contribution from the making of cement.
I’ve already mentioned the large number, the 10 gigatonnes. One of the problems of communicating climate change is that we have to deal both with very large numbers and very small numbers, and it is quite difficult to get our heads around them. 10 gigatonnes is a very hard number to think about. But equally the number on the other side seems very small; which is that on average the temperature of the surface of the planet has increased by about 1 degree centigrade since about 1900. That doesn’t sound like very much, but it is very unevenly distributed around the planet so some parts are warming up much more than others.
What we are actually seeing, as much as climate warming, is climate disruption. What we are seeing, in any system that you look at, is the changes that you would expect to see if the planet is gradually warming - so for example:
- a reduction in the volume of glaciers
- an increase in air and sea temperatures
- sea levels rising by about 3mm each year - partly due to thermal expansion, but partly due to the run-off of snow and ice
- reduced snow cover
- reduced arctic ice
The evidence is unequivocal that we humans are changing the climate of the planet.
That is the description of the problems, now what is the way forward?
I have already said something about the enlightenment. This museum was formed as a result of the enlightenment; it was our inquiry about the natural world, our trying to understand it, our development of the scientific method and more rigorous methods of exploring how the planet works. It was that enlightenment that was so important in creating this museum.
I think the challenge for us now is to use our intellect and our undoubted technological capabilities, to try and deal with some of the challenges that we and other species now face. I think we need an enlightenment 2.0.
There are some things that we can do a lot about and there are others that we really can’t do too much about.
You see [on the right] a somewhat fanciful image of an asteroid hitting the planet, and there is certainly not too much we can do about that at the moment. You see [on the bottom] the result of an enormous effusive volcano; so if the caldera at Yellowstone erupted in a very spectacular way. There is not too much that humans can do about those type of events. There is no question that both of those events would have very dramatic affects and might trigger another mass extinction on the planet.
But there are things [on the left] that we can do something about;
- we can do something to manage our populations
- we can do something for the climate
- we can do a lot about the environment and how we share our planet with other species
On climate there are really 3 options for us, we can:
The challenge for us is to optimise the ratio between these options and, if we are to do that, we have to use all of our creative abilities and technologies to take this on.
The push of population
It is very difficult to give this talk without saying something about population. The interesting thing about population is that the paradox is that, as societies develop, and as we improve both maternal and child health, the evidence shows that human population starts self-regulating their numbers.
What you see here [on the top left] is what is sometimes known as the demographic transition. We start with a high death rate and a low population. Then what happens is we go through a period when the death rate falls, but the birth rate remains the same - that is the period in societies where we have explosive population growth. But then if we can get over this phase, with death rates down dramatically, then all the incentives are for people not to have lots of children. And that is what we see happening in societies around the world. It becomes an economic advantage to have no more than 2 children. All the history shows that societies will at some point self-regulate their numbers.
Of course technology has also helped here, and it is technology that helps with population growth.
My argument now, and for the rest of the talk, is that if we are going to come to a better equilibrium with the other species with which we share the planet, we really have got to use all the technology that is within our grasp and develop new technology to make this successful.
Diverse energy sources
On energy I illustrate some of the opportunities on this slide.
One of the things we can do if we want to continue to burn fossil fuel is to capture the carbon which is emitted as a result of burning fossil fuels; reversing really the creation of the atmosphere that happened in the first place - we are going the full cycle. The micro-organisms created the atmosphere for us, they died and became fossils, and what we are doing at the moment is burning them and putting the carbon dioxide back in the atmosphere. It is technologically possible, although not yet really cheap enough, to do carbon capture and storage.
We can avail ourselves of the extraordinary energy source which is the sun.
We can use wind power.
We can use natural gas, which is a better fossil fuel to use than coal.
We have to use diverse energy sources. There is no one size that will fit all; we can’t be dependent on a single energy source.
If you think about energy, and how both policy-makers and we as society think about energy, we look at it through 3 lenses. And they are 3 lenses which actually affect our view on many things.
On energy we must have security of energy supply - if the lights go out in London then London descends into civil unrest potentially quite quickly.
We have to be able to afford our energy - because our economy matters.
And thirdly we have to have energy that is sustainable in terms of the planet itself.
Often we have to think about all of these things; we have to think about our food in the same way. We have to have food that is secure, so we have to have security of supply. It has to be sustainable and it has to be affordable.
And that is again and again the challenge for policy-makers and for technology. If we look at the world through any 1 of those lenses alone, then we are unlikely to come up with a policy solution that is entirely realistic.
The last slide talked about energy power production, but the other side of the coin is energy consumption. We have to find ways to reduce our energy demand:
- the electric car running on de-carbonised electricity
- the smart meter that helps us manage our electricity usage at home in a way that is more sustainable and hopefully cheaper
- a piece of technology from the 19th century - although Leonardo thought of it first - the bicycle
We have to find other ways of getting around which are not only more sustainable, but are actually better for our health as well.
So we have to reduce our demand as well as our generation of electricity.
For almost any area of society you look at we need to find better ways.
We take water security for granted, but in many parts of the world there is no water security at all, and it is our water systems around the world that are under enormous stress.
So it is not only reducing our demand through better and more effective mechanisms of sanitation, we have to look at the whole cycle of water and work out how we can make it more sustainable and reduce our demands on it.
To finish in an area that I already gave you fore-warning of; I think we have to be a bit more sensible in our public discussion about food and food technology.
Going back to the Teosinte - the precursor of modern corn or maize - this was produced using the selective breeding approach which we have done historically. If you look at the differences between Teosinte and modern maize, there are literally millions of genetic changes between them. The number of chromosomes has been doubled - normally that is quite an unhealthy thing to do. We wouldn’t like it if our chromosomes were doubled. The chromosomes have been extensively rearranged; there have been insertions and deletions. This took about 7,500 years to do.
If ever there was a genetically modified organism, it is maize, and we consider that entirely safe to eat.
Here [on the right] we have the potential that biotechnology offers, which is not about millions of changes, but about a tiny amount of genetic material. It is about putting it in a precisely known place in the plant genome. It is about knowing what we are doing and being able to test the consequences rapidly.
These organisms, which are known as GMOs, are trivially genetically modified compared to the plants that we take for granted as our food stuffs, and yet we doubt the food safety of these.
If we are going to be able to feed large populations, then we need to use all of the technology that is available to us in order to develop plants that enable us to use land more sustainably. If we want to reduce the use of pesticides - and who wouldn’t want to reduce the use of pesticides - then surely the sensible thing is to breed plants that are naturally resistant to the pests.
There are all sorts of ways in which we can, and indeed must, use technology to enable us to share our planet, not only with other species, but with each other as well, in ways that are more sustainable.
This photo I took yesterday sitting in a hide at Minsmere. It seems to me that this epitomises how we need to share our natural environment with the technology that give us the lifestyles that we have become used to and indeed somewhat addicted to. Here you see the reed beds at Minsmere and behind them is Sizewell B nuclear power station generating more than a gigawatt of energy. This surely is bringing together low carbon technology with the natural environment in a way that is harmonious. There just conveniently happened to be a flock of mute swans flying past at the time.
I want to leave you with a challenge.
The Natural History Museum needs to be one of the key places where we discuss how we can share the planet most effectively. We are discovering new species virtually every day of the week, and our understanding of the microbial world is really near its beginning rather than near its end in the ability to discover many species that we simply didn’t know existed.
So I hope I have given you an idea of some of the things that humans have done in terms of sharing the planet with other species. We have hunted them, we have moved them, we have evolved them by breeding programmes, and we have also modified the environment of the world in extraordinary ways.
There is a columnist who describes himself as the rational optimist. I think the challenge for us is to be as rational as we possibly can in recognising the challenges, not only to ourselves, but to the species with which we share the plane; to use all of our technological might to develop ways in which we are going to be able to continue to share the planet with ourselves and other species in the future.
Thank you for your attention.