Environment correspondent, BBC News website, Barcelona
At least 25% of the world's mammal species are at risk of extinction, according to the first assessment of their status for a decade.
The Red List of Threatened Species says populations of more than half of mammalian species are falling, with Asian primates particularly at risk.
The biggest threat to mammals is loss of habitat, including deforestation.
But there is good news for the African elephant, whose recovery leads to removal from the high-risk list.
This year's Red List looks at 5,487 mammals, and concludes that 1,141 are currently on the path towards disappearance. 
This may be an under-estimate, the authors caution, as there is not enough data to make an assessment in more than 800 cases. The true figure could be nearer to one- third.
"Within our lifetime, hundreds of species could be lost as a result of our own actions, a frightening sign of what is happening to the ecosystems where they live," said Julia Marton-Lefevre, director-general of the International Union for the Conservation of Nature (IUCN) which publishes the Red List.
"We must now set clear targets for the future to reverse this trend, to ensure that our enduring legacy is not to wipe out many of our closest relatives."
The report's authors said the current concern with financial matters must not be allowed to obstruct the decline in the Earth's natural systems.
"The financial crisis is nothing compared with the environmental crisis," the deputy head of IUCN's species programme, Jean-Christophe Vie, told BBC News.
"It's going to affect a few people, whereas the biodiversity crisis is going to affect the entire world. So there is a risk that because of the financial crisis, people are going to say 'yeah, the environment is not that urgent'; it is really urgent."
About 40% of mammal species are compromised because human expansion is putting a squeeze on their habitat.
This is especially important across the tropics, the regions with the highest diversity of land-based mammals.
South and Southeast Asia are identified as regions where extinctions are especially likely in coming years, as that is where the size and living standards of the human population are rising fastest.
The second biggest threat on land is identified as hunting, for food or medicines.
However, where hunting has been controlled and conservation programmes implemented, as with southern and eastern populations of the African elephant, populations and entire species can recover.
The elephant's risk status is lowered from Vulnerable to Near Threatened.
Some species are included for very specific reasons, such as the Tasmanian devil which has been decimated by a viral cancer.
In the seas, bycatch - entanglement in fishing nets, which is usually although not always accidental - emerges as the biggest factor behind current declines, affecting a staggering 79% of marine mammals.
The assessment - which is also published in the journal Science - warns that lack of data about marine mammals may be masking a bigger decline.
"Whales, dolphins, porpoises, and sirenians (manatees and dugong) are so difficult to survey that declines that should result in a Vulnerable listing would go undetected at least 70% of the time," the authors write.
Outside the mammal arena, the Indian tarantula enters the Red List for the first time, a consequence of over-harvesting for the pet trade.
A further 366 amphibians have been added to the list. This is the most threatened animal group of all, with about one-third on the high-risk list.
A new assessment of climate impacts on the natural world suggests that many species not currently on the danger list will enter it as temperatures rise, particularly in East Africa and parts of South America.
In picturesThe Red List is published approximately once every year. Although designed as the definitive global list of threatened species, in practice the rankings come from assessments covering different types of plants and animals, and some areas of the list will be more up to date than others.
An assessment of sharks, originally slated for inclusion this year, was delayed and will probably be released later in the year.
In an attempt to make species assessments more certain, the Zoological Society of London (ZSL) is developing what they colloquially term a "Dow Jones index" for biodiversity.
The idea is to take a random sample of all the world's species, which will be representative of the whole, and revisit it regularly - perhaps once every five years - to gain a better idea of global trends.
"We are now emerging from the dark ages of conservation knowledge, when we relied on data from a highly restricted subset of species," said Jonathan Baillie, ZSL's director of conservation programmes.
The first group to be assessed this way is the land-dwelling vertebrates, but the project will eventually encompass insect, fungi, plants, and various types of marine creatures.
More than 8,000 conservationists and policy makers are in Barcelona, Spain, for the IUCN World Conservation Congress.
Held once every four years, the gathering is viewed as a landmark event where future conservation strategies are developed.
In his daily diary, environment correspondent Richard Black reports on the topics beings discussed in the conference halls, and visits some of the fringe events.
Having delegates fly in to international conferences isn't very smart when the conference has a strong environmental theme and aviation is widely seen as Public Carbon Enemy number one.
Messages about saving the planet do not mix well with talk of air miles and upgrades - though the mix does happen.
OK, so most green groups offset these days - but that's not a flawless process.
Hence the decision by the World Conservation Congress organisers to invite delegates to sail.
Blown by the wind, navigating by the stars, perhaps doing a little sustainable fishing on the way - what better way to arrive ethically and climatically clean.
So the bright Catalonian morning saw perhaps 15 boats, maybe a few more, moored up in the dock before making the short hop to the conference centre itself, where they would "deliver their message".
The message appeared to be that more awareness of issues like climate change, biodiversity loss and marine pollution would be a good thing - which probably 99% of people in the conference centre would agree with anyway.
Stormy waters
There were some interesting vessels on display, ranging from the mighty research ship MarViva (which I mistook for a tug at first sight), complete with submersibles and an engine that racked up decibels with the abandon of Led Zeppelin, down to ordinary yachts.
One that caught my eye was the Tara, a futuristic metal-hulled research boat which has just spent 16 months drifting in the Arctic. Yes, drifting - allowing itself to become enmeshed in ice when the ice built up - although director Etienne Bourgois told me the ice turned out to be about half as thick as they were expecting.
Tara facts three and four: when ice converges on the boat it is lifted out of the water onto the floes, with no damage; and the crew spent 18 months seeing no-one but each other.
Then there was the Largyalo, a catamaran with giant canoes as the bits that go in the water (I believe they're still called hulls on a catamaran but don't quote me).
The inspiration was Polynesian, the boat's "constructor" Petra told me. It's sure to catch attention during its planned 1,000-day, 100-port trip raising awareness about climate change.
And that is really the point. The initiative was called Sailing to Barcelona, but delivering their message here will be as plain sailing as you can get - everyone wants to hear it.
The big world is a stormier place, where the worthiest messages get tossed around on angry seas, and sometimes wrecked before their time. 
MONDAY 06 OCTOBER - SEEING RED
One is saying "we've heard it all before"; another is asking "so what?"
A third is contending "I don't believe it", while its less robust companion bewails "there's nothing we can do".
These voices are very familiar. They bug me every year when the Red List of Threatened Species comes out, and they were particularly prominent last year around the launch of the UN Environment Programme's Global Environmental Outlook (Geo-4).
They are all saying things that in their own way are quite sensible.
We have heard it before - the message of environmental doom is very familiar to anyone who reads further than Heat magazine and the immigrant-petrified middle tabloids.
The implications of biodiversity loss are nebulous next to a train crash, disaster seems hard to credit when our cat is well fed and the car works, and there probably is nothing that we can do.
So does that mean it is not worth hearing that 25% or 30% or 12% or 45% of one or other group of species is heading down the path to extinction?
If I was about to be hit over the head with a large stick, I would prefer to know.
If a quarter of the world's mammals are heading for the mortuary drawer, again, I would like to know, even though I might not have a clue how to stop it.
In fact, working out how to stop it is probably the hardest task facing the human race. Nuclear disarmament looks like a doddle by comparison, because the root causes of biodiversity loss are simply what our successful species does to live, eat, develop and expand.
Presumably we are going to keep doing those things. So presumably other life-forms, less adaptable, will feel a tighter and tighter squeeze.
Until something gives.
Buying the argument
"Haven't you always wanted the chance to live a sustainable lifestyle?
"Well now you can, thanks to the government's Sustain-a-bill!"
Unless I am mistaken, this is the future of advertising - at least, as foreseen by a panel of luminaries connected with the industry who held a post-tea break discussion at the congress.
"The advertising and marketing services industry has in part been responsible for encouraging overconsumption," Sir Martin Sorrell, CEO of the marketing services group WPP, admitted in a pre-recorded video message.
"But we've but come to a stage where overconsumption is not necessarily the best route to follow, so responsible consumption is becoming increasingly important."
He picked out events that he believed showed businesses were transforming their paradigms towards sustainability, such as Rupert Murdoch's espousal of carbon neutrality and Richard Branson's investment in low carbon energy.
Dean Sanders, a former Kraft executive who now runs the marketers GoodBrand and Co, argued that advertisers weren't responsible for advertising environmentally damaging products - it was the fault of the companies that made those products.
And Cheryl Hicks from the World Business Council for Sustainable Development (WBCSD) suggested advertisers could help sell people on a sustainable, low carbon, environment friendly lifestyle, if governments would only engage them to do so.
So there we are. Advertising and marketing agencies, or at least this small sample, see themselves as part of the solution to the growth in consumption that lurks - together with population growth - behind every other environmental problem.
Buy a used Red List, anyone?
Russell Mittermeier
Climate change could actually benefit some of the world's most endangered species, says Conservation International president Russell Mittermeier. In this week's Green Room, he explains that conservationists should capitalise on the worldwide attention being given to global warming.
Climate change could be the best thing that ever happened to the amazing array of animal and plant species that make up the Earth's biodiversity. Don't get me wrong; climate change is the most serious environmental threat we have ever encountered, and it is already taking a terrible toll on species, as well as people, all over the world.
The silver lining is that climate change has triggered a universal wake-up call that we all hear, and are beginning to heed.
Never before have so many sectors of society been equally concerned and motivated to combat an environmental threat.
Of course, some die-hard pessimists say it's too late, that the climate change train has left the station and there is nothing we can do but get ready for catastrophic consequences.
Nothing could be more wrong. Just ask the thousands of participants at the World Conservation Congress (WCC) now taking place in Barcelona, Spain.
Representatives from governments, indigenous peoples, industry and environmental groups are meeting to present innovations and create partnerships.
Climate change and protecting species are focal points, and pessimism is not on the agenda. Instead, smart constructive ideas for solutions are being shared.
We estimate the Earth harbours a minimum of six million living species, from microscopic bacteria to magnificent great apes.
The major news announced at the WCC on Monday was that the latest assessment of the world's mammals shows more than 20% to be threatened with extinction.
That includes 188 mammals, such as the Iberian Lynx, in the highest threat category of Critically Endangered.
This assessment is part of the IUCN Red List of Threatened Species, which now includes 44,838 species, of which 16,928 (38%) are threatened with extinction.
Self preservation society
Why should people care about the fate of these plants and animals?
In the most simple terms, we should care because the quality of our lives ultimately depends on them.
Without species diversity, we wouldn't have the healthy ecosystems that supply our food, cleanse our air and water, provide sources of life-saving medicines and help stabilise our climate.
We would also miss out on a free and ubiquitous source of miraculous beauty and endless possibilities.
We continue to discover new species every day. Just since 1994, we've discovered 54 new lemur species on the Indian Ocean island nation of Madagascar.
The thrill of documenting a new primate is tempered, however, with the knowledge that many species will become extinct before they are even discovered.
On a global scale, we're losing species 1,000 times faster than what scientists consider normal.
It is an insidious, silent epidemic that could wreck our planet's ability to heal itself.
While the Red List does make headlines, somehow the irreplaceable loss of species does not stay in the minds of the general public, and it has certainly never prompted major financial investments.
This has always puzzled me. As a colleague of mine puts it: "Imagine what would happen to us if rainfall was a thousand times more than normal? What if snowfall were a thousand times more than normal? What if rates of disease transmission for malaria or HIV/AIDS were a thousand times higher than they are now? That is what is happening to plant and animal biodiversity today."
Just as climate change threatens us with rising sea levels, droughts, floods and more category five hurricanes, it is also one of the greatest threats to species.
We could lose more than 30% of the Earth's plants and animals this century due to shifts in the Earth's climate.
So where is the silver lining?
The good news is that the unprecedented spotlight on climate change is also shedding light on how tropical forests balance our Earth's climate.
At least and possibly much more than 20% of the greenhouse gases that contribute to climate change come from forest destruction - that's more than from all the world's cars, trucks, airplanes and trains combined.
At the same time, forests are effectively our life support system, absorbing carbon dioxide and emitting oxygen.
Those same tropical forests are also home to the world's greatest preponderance of species diversity.
Remove the forests and you will also exterminate countless species. By the same token, the species are essential to healthy forests for many reasons, including pollination and seed dispersal.
There is still time to protect these forests while also providing economic opportunities to developing countries and local people.
One of the key issues at the WCC in Barcelona is how conserving standing tropical forests to fight climate change must be included in a new United Nations agreement to replace the Kyoto Protocol, the current climate change treaty that expires in 2012.
If we ensure that nations will be compensated for forest conservation that reduces emissions, we will also contribute to redressing some of the huge economic imbalances that exist in the world, since many tropical forest countries are among the more economically stressed.
A message Barcelona can send to the rest of the world is that it is not too late to protect species as well as combat climate change.
On both counts, the welfare of humanity is at stake.
Russell A. Mittermeier is president of Conservation International and chairman of global conservation group IUCN's Species Survival Commission's Primate Specialist Group
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
Do you agree with Russell Mittermeier? Can the focus on climate change be positively harnessed by conservationists? Will paying tropical forest nations be a way to tackle climate change and protect biodiversity for future generations? Or has the climate train left the station and we must prepare to face the consequences?
Some people are here with both their IUCN SSC and ASG hats on.
Others are seeking to mainstream stakeholder buy-in for cross-sectoral biodiversity financing.
In some rooms you can perch at the interface between ZERI and the WBCSD.
So it was refreshing - no, it was a paradigm-breaking uplift scenario - to see, on today's agenda, a session on how to break through the jargon barrier that keeps many of the issues discussed here sealed within the small circle of people who speak the same language.
The Red List is simple to communicate. I can do it in two words - "we're ….d" - in the modern spirit of interactivity, you can choose which word to use as the second.
But most sustainability-speak is far too jargon-laden to translate to the world outside these walls, however important the ideas themselves. I think everyone here knows it, but no-one quite knows what to do about it.
The session didn't quite live up to its title. Rather than clearing up the language, speakers chose to look at methods of getting things across.
Somewhat inevitably, once the first speaker had promised us an exciting new way of communicating biodiversity loss and reached for her computer mouse, technical gremlins came out from their hiding hole and it ground to a halt.
The Google Earth on screen looked to be in no better condition than the real one.
Forest flaws
Back in the UK, environmental groups have been busy pressurising the government to meet its various targets on cutting carbon emissions by - well, by cutting carbon emissions, rather than by buying measures from overseas that result in equivalent carbon savings.
I had a different take on the issue today from Russ Mittermeier, president of Conservation International, a major US-based environment group.
The core of its work is in developing country ecosystems such as rainforests, attempting to preserve places where nature can work.
Russ wasn't so sure that making all the changes at home was such a good idea.
When preserving forests is generally believed to be the cheapest way of curbing climate change, and when it has so many side benefits for the fresh water supply, for animals and plants, and for people who live off the forest, why not prioritise spending money on that?
"The danger is, you end up with nice clean energy systems at home, but you've lost the rainforest," he said.
In the dash to biofuels, campaigners forgot about biodiversity in their haste to find a climate-friendly transport solution.
There are good counter-arguments to Russ Mittermeier. But his point should surely remind us again of the dangers of separating the world's various environmental ills, and trying to solve them separately.
