By Alex Kirby
Our environment correspondent considers why warnings about the state of the planet are becoming more insistent
For the doom merchants amongst us, 2004 showed its fearsome teeth in a cracking start before it was even 10 days old.
The strains are showing
On 7 January a report in the journal Nature said climate change could speed a million land-based species towards extinction within the next 50 years.
The next day the Worldwatch Institute declared modern lifestyles were bad for us and unsustainable for the planet.
The UK Government's chief scientist now says climate change is a far worse danger than international terrorism.
A triple onslaught like that defies anyone to head into the new year feeling even slightly positive about the human condition.
Yet life goes on, and most of us worry more about paying the Christmas bills than about a world bereft of a quarter of its animals and plants.
We believe the scientists: we simply do not connect their findings to our lives, our families, ourselves even.
Some of us just refuse to react, blaming the messengers for their message and accusing the scientists of scaremongering.
Many species' prospects are dim
But (at the risk of tempting fate) my inbox has been blessedly much freer recently of flat-earthers and foam-flecked contrarians (and I do not regard most of those I disagree with as being either).
Most of us are convinced by the message - yet still we go on as if we had not a care in the world.
But whether because of climate change or not, we are already losing species so fast that biologists talk of the Earth undergoing its sixth great extinction since the Big Bang. We are losing species we do not know exist, which could be vital to our survival.
A few years ago, when the world's gross national product was worth about $18 trillion, the value of Nature's goods and services to us was estimated at $33 trillion.
Similarly, the evidence that human activities are intensifying natural climate change is impressive, and hardening. The world really is changing, almost imperceptibly, but in line with what science says will happen.
Slow to show
I know there are sincere people who regard both the global extinction rate and the changing climate as entirely natural developments which need not concern us.
But I met a man recently who told me how he could see the effects of the warmer climate in his local park in Birkenhead, in the north of England.
I talked to another whose research has convinced him there may be only 20,000 lions left in the whole of Africa.
Icecores hold many secrets
The trouble with imperceptible change is that for a long time it has virtually no impact, certainly not on the political timescale of four or five years. And politicians respond (often) to what they think matters to voters.
Yet the record preserved in cores drilled out of the Greenland icecap shows climate change can be very rapid indeed, flipping from one stable state to another in a few decades.
It is not fanciful to envisage our children living in a Britain where the Gulf Stream has ceased to flow, and where climate change means winters as cold as northern Canada's.
Perhaps it will take some sudden, savage reversal of Nature to make us sit up and take notice.
But we can change just as unpredictably as Nature can. Who predicted the peaceful end of apartheid South Africa, the melting of the Soviet Union?
When enough of us have changed imperceptibly enough to start acting on the warnings we are hearing, the resulting critical mass will cause some very rapid change of its own.