For those people who have been living in a total isolation, cut off from all other people and forms of communication for the past week or two, it may astonish you to know that the naturalist and tv presenter Sir David Attenborough turned 100 this month.
Yes, he’s lived exactly 100 years on Planet Earth. That means he was born between the two world wars, and in the same year as the UK General Strike took place, the same year as liquid rocket fuel was invented and the same year that Mussolini properly consolidated his power in Italy.
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During his extraordinary lifetime, the world has changed almost beyond recognition – and here’s how.
Tropical rainforests
The world’s tropical rainforests are often considered a proxy for how humans have impacted the planet over the past century. That is surely because they not only contain an astonishing diversity of often remarkable wildlife, but also because they are so important as regulators of global climate patterns.
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Sad to say, there has been a huge reduction in their cover since Sir David was born – the estimates are that the original extent was around 15 million km2, an astonishing 10 per cent of the land surface of the world, and that has shrunk to between 9-11 million km2 today, a loss of between 33-40 per cent. The Amazon and Congo Basins are still the two largest continuous rainforests in the world.
Big cats
The threats to big cats such as lions and tigers are also an indication of how much the natural world has been depleted over the past 100 years.
The consensus is there were about 200,000 lions in the world in 1926, with most in sub-Saharan Africa, but some still surviving in North Africa, the Middle East and India. Today, there are somewhere between 23,000-39,000 (and probably the lower end of that), almost all in southern and East Africa.
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Tigers have suffered even greater declines – there were 100,000 at the turn of the 20th century and today an estimated 5,500, though numbers have increased by more than 2,000 in the past 15 years thanks to intensive conservation efforts, especially in India.
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Baleen whales
Baleen whales – the group of cetaceans that includes species such as blue whales, fin whales, humpback whales and minke whales – have also suffered huge declines, but the biggest impact took place before Sir David was born. So-called industrial whaling had already more than halved the ‘great whale’ populations by the 1900s, and while the 20th century did see further reductions, they were not as significant.
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Already by the 1960s, there were so few blue whales (perhaps 1,000) and humpbacks (perhaps 10,000) that they weren’t worth hunting any more. Humpback whales, in particular, have largely recovered in the past 50 years or so. In total, the whale population may have numbered 1.5-2.5 million in 1926 and is estimated at 1.3-1.8 million today.
Extinctions
Many human-caused extinctions – such as the dodo and the passenger pigeon – also took place before Sir David was born, but there have been several notable ones during his lifetime. The the dog-like carnivorous marsupial, the thylacine or Tasmanian tiger, and the freshwater river dolphin known as the baiji, which was endemic to the Yangtze in China, are two of the most infamous.
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The golden toad of Costa Rica, the Hawaiian honeycreeper called the po’ouli and the Caribbean monk seal are three others. Absolute numbers are hard to pin down because we don’t even know how many species there are on Earth, but the IUCN says more than 900 extinctions have occurred since 1500 (with the vast majority since 1900), while one study published in 2015 concluded we’d lost 468 vertebrates in the same time period.
Farmland
The destruction of natural habitats in order to farm the land is usually given as the biggest factor in wildlife declines. You’d think, then, there would have been a massive increase in the extent of farmland over the past 100 years, but that’s not the case.
The total farmed area in 1926 was around 45 million km2 (around one third of the Earth’s total land area) and it’s about the same or a tiny bit more today. This is astonishing because there are four times as many people today as there were back then – more than 8 billion now compared to 2 billion.
But agriculture is far more intensive today, which is one reason for many of our wildlife losses. On the plus side, in some parts of the world such as New England in the USA and parts of Europe and the former Soviet Union, land has been abandoned and forest or natural grassland cover is on the increase.
Motor vehicles
The rise in ownership and use of motor vehicles – especially cars – has been one of the biggest trends of the 20th and early 21st centuries.
In 1926, there were an estimated 30-40 million cars, vans and lorries, most of them in the USA and Western Europe, but today there are a staggering 1.7-2 billion, a 50-60-fold increase. (And that doesn’t account for motorcycles and scooters, which may number 700,000-900,000.) Put another way, when Sir David was born there were 17 vehicles per 1,000 people – today there are 230.
Global temperatures
The biggest environmental threat today is almost unarguably climate change. Rising temperatures are causing some parts of the world to become uninhabitable and also leading to rising sea levels that threaten coastal communities and (probably – see below) causing more extreme weather events. Since 1926, global temperatures have risen by about 1.2˚C (and by 1.5˚C over pre-industrial levels), with at least another 1-1.5˚C rise predicted to come.
Almost all scientists say climate change is caused by increasing quantities of carbon dioxide (which is emitted when burning fossil fuels) in our atmosphere – this has increased from 280 parts per million (ppm) before 1850, to just over 300ppm in 1926 and 425ppm today.
Extreme weather events
So, has this rise in global temperatures and carbon dioxide in the atmosphere led to an increase in extreme weather events, as predicted by climate science? Well, probably. According to EM-DAT, the International Disaster Database, the number of major weather events a year in 1926 was 50-100, while in the period 2000-2010, there were 3,536 – about 350 a year, a 3.5-7 times increase.
But some of this rise – and nobody knows how much of it – is almost certainly down to better reporting of these events, so what the true increase has been is impossible to tell.
Human mortality
OK, let’s look at some good news. When Sir David was born, the average human could only expect to live to the age of between 30-35. This sounds alarming, but remember that it is heavily skewed by infant and child mortality, especially, being much higher than it is today.
Many people who made it into adulthood could expect to live into their 60s and 70s. Today, global life expectancy today is 71-73, so double what it was. And while it is impossible to state these things with absolute certainty, world poverty levels have also improved – in 1926, it’s estimated that 80-90 per cent of the 2 billion population lived in extreme poverty. Today, it’s around 650-750 million people, less than 10 per cent of the 8 billion population.
Birdwatching
In some ways, it could be argued that we value wildlife more today than we did in 1926. Again, these figures have to be treated with caution, but back then, there were probably no more than a few hundred thousand people who might be called birdwatchers. Today, the figure is 80-150 million, an increase of somewhere around 300-fold.
This has been permitted by the rise in relative affluence of people in the west (but also in countries such as India where wildlife-watching and wildlife photography are increasingly common) and technical advances in optics for binoculars and cameras, plus the rise of the conservation movement.
And it is also undoubtedly true that the life and career of Sir David Attenborough has also played a significant part in turning people onto immense and simple pleasure to be had in observing our sadly diminishing natural world.
