Megafauna Extinction Due to Climate

jvchamary writes "Most biologists believe that Earth is currently undergoing its sixth mass extinction. The cause? Human activity, either directly (e.g. the Dodo) or indirectly (e.g. the Amazon rainforests). The disappearance 30,000-45,000 years ago of the Australian megafauna, large animals such as the marsupial lion, is often attributed to hunting by Aboriginal settlers. However, recent research in Proceedings of the National Academy of Sciences suggests that it was more likely a shift in climate, rather than hunting, that caused the over-sized organisms to die-out (via Nature and the BBC)."

Comments

WOOT!

[Anonymous Coward]

We Win!

mmmm .... marsupial burgers

[Anonymous Coward]

I envy early man and his wider variety of animals to eat

Part of Nature

[ndansmith]

Human Beings are as natural a part of the Earth's ecosystem as earthworms and aardvarks. We need to accept that our behavior will affect the planet not unlike any other animals.

However, this is not an excuse for an "anything goes" attitude. We still need to work hard to preserve the earth; it is one of our greatest responsibilities.

Solar Activity Coinciding with Climate Change

[bacon55]

There's a lot of evidence to link large scale climate change with periods of heightend and lowered activity in the Sun.

Taken From "http://www.exploratorium.edu/sunspots/"

From 1645 to 1715, there was a drastically reduced number of sunspots. This period of reduced solar activity, which was first noticed by G. Sporer and was later investigated by E.W. Maunder, is now called the Maunder Minimum. This period of time was also unusually cold on earth, and it has been referred to as the "Little Ice Age." This has led to some speculation that sunspot activity may affect the earth's climate. Similar periods of low solar activity seem to have occurred during the Spoerer Minimum (1420-1530), the Wolf Minimum (1280-1340), and the Oort minimum (1010-1050). Solar astronomers label solar cycles from one minimum to the next, and assign them numbers, starting at one, with the 1755-1766 cycle.

Personally, I've always found it rather arrogant to believe we are the greatest cause of climate change on Earth. Lol, it could be that the Sun is literally causing us to use more energy...but thats taking the butterfly effect a little too literally - maybe.

Re:Bummer...

[Rei]

Don't give it up so quickly. There are some huge problems with the "climate-only" theory. Namely

A) In most of the world (even if not for some animals in Australia) extinctions were timed, as well as we can measure, with the arrival of humans into each region, even though the global climate was changing as a whole

B) Species survived far more dramatic climate changes in the past, with nowhere even approaching the degree of megafauna losses. The scale of megafauna losses last ice age was staggering - for the largest animals, often over 90% of species.

C) We've seen this occurring in more modern times. For example, the Moa of New Zealand; there is essentially no doubt that they were butchered by the Maori, because their fossilized cooking pits are filled with Moa remains in nice neat layers - huge numbers of them that the species clearly couldn't have sustained. When the Maori were discovered, they talked about hunting and killing them. There's a sudden cutoff point in Maori sites in which suddenly Moas disappear from the diet.

Also, climate change isn't the only alternative theory. There's also the concept of humans being a carrier for diseases/pests, human-induced environmental changes, human killing of "keystone" species, and my favorite, "many of the above combined".