The 6th Mass Extinction | Dr Dominique Dodge-Wan | TEDxCurtinUSarawak

I've got a quite important message today it's about what's happening in the world I'm going to talk to you about the sixth mass extinction the one that's happening right now as we talk here in this room extinction is normal it's a normal part of evolution but what's happening right now is faster than anything that's been seen before in the geological history mass extinction is extinction of a large number of species plants and animals from many different habitats all over the world in a short period of time so I'm pleased to see lots of geologists in the room geologists have a unique perspective they have a chance to look back in time and to see what happened before so what do we find we find if we look back at the last five hundred million years we find five big mass extinctions the big five the causes for these now well known you've probably heard about the extinction of the dinosaurs caused by an asteroid impact some of the mass extinctions were due to climate change massive volcanism where lava spews out - fissures and changes the Earth's geochemistry over thousands of years climate change which can have a knock-on effect on things like sea level but what's happening right now is of a different order some a predator is on earth and usually the apex predator is not the most abundant but in the case of humans yes right now we are experiencing the sixth mass extinction bigger question mark it's still ongoing we can't quantify fully faster no doubt the numbers prove it and the cause is single it is us humans here on earth and our impact so what does the science tell us there is a lot of science there are biologists conservationists all over the world studying different species from microorganisms to polar bears in all different countries different habitats they're coming up with the same sad story the International Union of conservation for Nature has set up what they call the Red List this has been going on for about 40 years every couple of years the Red List is updated the numbers seem to be increasing we study more organisms and we find the same story there's a sliding scale vulnerable endangered critically endangered and finally extinct it seems that many species follow this scale there's a sort of slippery slope it's extremely difficult although not impossible thankfully for species to go backwards along the scale there are some examples where a species that was extinct in the wild have been successfully reintroduced there are also examples where a population in decline has been safe from extinction unfortunately it's not the majority let's look at the trends this is just a chart showing some groups corals are particularly badly affected 30% decline birds mammals amphibians and this is across different ecosystems in different climate zones all over the world should we be alarmed yes the current trends are alarming I've just chosen two quotations from prominent biologists probably the world's best-known conservationists the present extinction rates a thousand to ten thousand times the natural rate we are in a mass extinction Yeoh wilson i hope you've heard of him probably the world's best known biologist if the current rates continue half of all animal and plant species will be extinct by 2100 that is in about three or four human generations think of your grandchildren everybody likes a picture of an animal so I've chosen the dodo I'm going to go through some of the causes we said humans are the primary cause of extinction let's go through some of the secondary causes how have humans affected species numbers that they're always extinct we have this expression as dead as a dodo the dodo is a flightless bird about the size of a turkey hint turkeys are good to eat when humans arrived on the island of Mauritius they thought that the dodo was quite good to eat too and has been hunted to extinction for food humans also brought with them alien species that didn't live on this island before dogs pigs goats etc those animals harvested at the dodo eggs okay it only took a hundred years to eradicate the species extinct forever the symbol of extinction and I'm going to show you now some other animals and plants I've chosen quite a diverse selection it's a bit like an identity lineup I could have chosen others and I could go on for about a month before running out of extinct or threatened species the silky sifaka this is a primate on the island of Madagascar which split from Africa about a hundred million years ago primates evolved totally differently from other parts of the world so the silky sifaka is one of about 30 lemurs that live in the forest they're critically endangered hunted for bush meat loss of habitat slash-and-burn agriculture logging and cutting of trees for few Elkhorn coral corals are very important because the coral ecosystem is the basis of the food chain in the oceans corals also provide protection for coastal areas breeding grounds for fish the Elkhorn coral is in decline this is a species that lives in tropical waters white band disease increasing ocean acidity ocean warming physical damage anchors tourism human pollution sedimentation and also invasive species that humans may bring around with them when they travel still in the seas and closer to home a bit closer to Iraq the Hawksbill turtle also critically endangered this is a species that once had a very large population thriving in tropical waters all around the globe now critically endangered the numbers are dwindling hunted for its beautiful tortoise shell trapped in abandoned fish nets and other marine litter lost of the nesting habitat and the foraging habitat marine pollution and tourism I believe that hard to find any Hawksbill turtle in waters around here anymore staying in the Southeast Asian aegeon Nepenthes a picture plant this plant is incredible it's evolved to capture insects it captures lemonade digests them in the in the juices that that sit at the bottom of the pitcher plant unfortunately it has a narrow habitat tolerance it only lives on certain areas in Sumatra the habitat being restricted if this habitat is damaged the species looks to be declining probably will not make it I couldn't give a talk and show animals without including a cave or at least a cave creature and to also show that human impact has even reached underground the Indiana bat a bat species that's found in Indiana Illinois Kentucky the cave regions of the United States used to be vast populations in winter they hibernate underground in caves in the summer they go into the forest to forage so it's tricky to conserve we must maintain there both habitats human disturbance in the caves commercialization of the caves too many visitors disturbing them urbanization and development around the caves changed the chemistry and the temperature loss of the summer forest habitats where they used to to forage endangered maybe we've still got time ok little cute creature the axolotl salamander how many of you have heard about it maybe one or two good this is a very unusual animal that's why I chose to to use it in my talk today it's a salamander that seems to have never matured to an adult so the adult axolotl looks a bit like a tadpole it's got its gills on the outside of the body you see that furry thing oh by the way the photo is a lab specimen it's very difficult to find Wikimedia Commons photo with actual in the wild they're so rare critically endangered they live in the canals and lakes around Mexico City one of the world's busiest and biggest developing cities they're very curious when you cut off their limb it can regenerate so there's a high interest in medical research using these animals unfortunately they also make convenient cute little pets they've been hunted for pets for consumption for medical research I forgot to mention that the axolotl is also an important character in the Aztec mythology in their culture the urbanisation desiccation of the canals in Mexico City pollution particularly bacterial pollution and invasive fish that were introduced by humans thought it's time to show a little plot okay miniature cactus that grows in New Mexico unfortunately once again very restricted habitat apparently only several square kilometers cute little cactus often people would like to have one in the little terrarium in their home so illegal collection has dropped the numbers urban development off-road vehicle use droughts there have been some attempts to reintroduce my talk is not entirely negative I hope there is ways of changing the situation they've been in reintroduce but it's a big effort and must be sustained for it to be successful I'll finish off with probably quite a well known animal that has suffered the golden toad okay this animal lives in in protected forests in Costa Rica protected forests it's important and yet it is extinct this is the first victim of global climate change not illegal logging of slash-and-burn agriculture this animal lived in a protected forest unfortunately the pools where it spawned have dried out and that caused the population to plummet last seen alive in the 1980s also suffered maybe disease and air pollution made them more vulnerable so that's the end of my little lineup of victims why should we care why should we care about this situation well you probably know that plants and animals provide us with what's called nicely ecosystem services our rainforests provide oxygen our forests also retain the soils and prevent soil erosion corals as I said earlier mangroves corals protect our coasts from erosion also the oceans are very valuable as a food source okay if we deplete that we'll end up in a terrible situation we only have one planet these animals and plants are our life-support system we have no choice but I also think it's very important to recognize we're all in this together we're all connected some of our previous speakers have mentioned this and to go with the emotive impact I think it's worth it just for the sake of it diversity is what makes the world such an interesting place and it resonates with humans we need nature on an emotional basis so what can we do we need to come up with some solutions we can classify their solutions into two categories two schools of thought and conveniently they're both symbolized on your bookmark today the arrow can symbolize reduce reduce growth reduce the human population I'm not talking for exterminating us that might happen without us wanting to but we have to stop rampant growth reduce our footprint reduce our impact on the environment especially that well the negative impact with juice consumption recycle reduced waste marine litter - greenhouse gases Oh linked to waste so this is the first school of thought maybe a little bit you could see this as going back in time a little bit to when things were not so bad the second school of thought let's find some technological fixes okay let's use alternative energies let's make our cars cleaner let's use resources in a different more sensible manner can we fix the damage done are there ways genetically modified organisms maybe nuclear energy I'm just throwing ideas ok can we fix climate change there are some ideas there - I'm not saying they're going to work I think personally and I'm more of the first school of thought but I think it's time for action the time for measuring counting populations is over we need to start doing something and it will be you our young students and your children who are going to have to take on this challenge I will finish by this saying which I borrow from Marco lambertini who is the director of general of WWF it is time for us to close the destructive chapter in our history if we don't we might find it's not only the end of the chapter but it's the end full-stop so I hope that's not too pessimistic but thank you for your time and attention [Applause]

Channel: TEDx Talks

Views: 26,564

Keywords: TEDxTalks, English, Malaysia, Science (hard), Activism, Conservation, Environment, Science

Id: _gDeTLnmX5M

Length: 18min 9sec (1089 seconds)

Published: Tue Jul 25 2017