Earth In the Midst of Sixth Mass Extinction: the 'Anthropocene Defaunation' 342
mspohr writes: A special issue of Science magazine devoted to 'Vanishing Fauna' publishes a series of articles about the man-caused extinction of species and the implications for ecosystems and the climate. Quoting: "During the Pleistocene epoch, only tens of thousands of years ago, our planet supported large, spectacular animals. Mammoths, terror birds, giant tortoises, and saber-toothed cats, as well as many less familiar species such as giant ground sloths (some of which reached 7 meters in height) and glyptodonts (which resembled car-sized armadillos), roamed freely. Since then, however, the number and diversity of animal species on Earth have consistently and steadily declined. Today we are left with a relatively depauperate fauna, and we continue to lose animal species to extinction rapidly. Although some debate persists, most of the evidence suggests that humans were responsible for extinction of this Pleistocene fauna, and we continue to drive animal extinctions today through the destruction of wild lands, consumption of animals as a resource or a luxury, and persecution of species we see as threats or competitors." Unfortunately, most of the detail is behind a paywall, but the summary should be enough to get the point across.
Re:But what IS the point they're making? (Score:5, Informative)
As someone who does carpentry and has helped build a couple houses over the past few years, this is patently false. You've been lied to by whatever environmentalist rag you subscribe to.
Most homes in the US are framed out of 2x4's cut from pine, floorboards are made of pine plywood, hardwood oak, cherry, and others are used for flooring. All of this comes from the timber industry, mostly from Canadian timber, but some more exotic stuff still comes from Brazil and Africa. My brother's floor is Brazilian cherry.
Some of that lumber is sourced from tree farms, but those tree farms are problematic as well - it takes years to grow them, and habitats establish themselves within those farms as they grow. The longer it takes to grow them, the longer it takes to offset losses in virgin forest. Hardwoods typically take over 30 years to be ready for harvest, longer if you want wider wood as you would need for 2x6 or 2x8 joists and furniture.
Re:no problem (Score:5, Informative)
Nobody is citing climate change and all the animals they cite in TFS were extinct well before humanity is supposed to have had an impact on the planet's climate.
How about TFA?
Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.
Across vertebrates, 16 to 33 percent of all species are estimated to be globally threatened or endangered. Large animals – described as megafauna and including elephants, rhinoceroses, polar bears and countless other species worldwide – face the highest rate of decline, a trend that matches previous extinction events.
The scientists also detailed a troubling trend in invertebrate defaunation. Human population has doubled in the past 35 years; in the same period, the number of invertebrate animals – such as beetles, butterflies, spiders and worms – has decreased by 45 percent.
As with larger animals, the loss is driven primarily by loss of habitat and global climate disruption, and could have trickle-up effects in our everyday lives.
Re:But what IS the point they're making? (Score:5, Informative)
They've been claiming for decades that if we don't do anything the sea will rise by 25m in two decades
You may want to check your sources. Likely you are being lied to, but not by scientists. More likely you've been reading denier blogs. Here is what the IPCC predicted 25 years ago: "For the 'Business-as-Usual' scenario at year 2030 global-mean sea level is 8-29cm higher than today with a best estimate of 18cm." - https://www.ipcc.ch/ipccreport... [www.ipcc.ch]
Since 1990 we've already had about 8cm of sea level rise so we have already already within the projected range and we still have 15 years to go. The rate of rise is accelerating. Even at the current rate we will see about 13 cm rise by 2030. More if acceleration continues. Not far off from the predictions of 1990. - http://climate.nasa.gov/key_in... [nasa.gov]
You are off by a few orders of magnitude whereas the scientists have already been proven correct.
Re:But what IS the point they're making? (Score:3, Informative)
This is incorrect. Some primitive people do live in balance with their environments, but that is only because the environment has become adapted to them over a long period of time. The environment that was there before their ancestors arrived was different, and possibly included a variety of megafauna that was hunted or pressured into extinction before the current "balance" was established. Primitive people often burn large areas of vegetation, and kill large predators that they perceive as threats or competition. The entire Australian ecosystem went through a massive change when the ancestors of the Aboriginal tribes arrived and burned the continent to the ground. A different "balance" was established over thousands of years before the Europeans arrived, but it was not any more "natural" than the balance that now exists with the Europeans living there.