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Despite suffocating population density and a history of reckless industrialization, Taiwan remains an island of globally significant biodiversity, as well as a country where finding wild creatures isn’t difficult.
The northern part of the country has a subtropical climate, while the south falls into the tropical climate zone. Because of the complex and vertiginous topography, there are places that swelter for several months each year, while others experience snowfall and freezing nighttime temperatures.
Crucially, Taiwan has been an island for something like 12,000 years, since the end of the Last Glacial Period resulted in rising sea levels. The lifeforms that established themselves
Do terrestrial geomagnetic field reversals have an effect on Earth s climate? Cooper et al.created a precisely dated radiocarbon record around the time of the Laschamps geomagnetic reversal about 41,000 years ago from the rings of New Zealand swamp kauri trees. This record reveals a substantial increase in the carbon-14 content of the atmosphere culminating during the period of weakening magnetic field strength preceding the polarity switch. The authors modeled the consequences of this event and concluded that the geomagnetic field minimum caused substantial changes in atmospheric ozone concentration that drove synchronous global climate and environmental shifts.
Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion
Abstract
Lake sediment archives covering several glacial cycles are scarce in the Southern Hemisphere and they are challenging to date. Here we present the chronostratigraphy of the oldest continuous lake sediment archive in Tasmania, Australia; a 5.5 m and 270 ka (Marine Isotope Stage 8) sediment core from Lake Selina. We employ radiometric dating (radiocarbon and optically stimulated luminescence) and relative dating (geomagnetic and climate comparisons). Bayesian modeling of the radiometric ages reaches back to 80 ka (1.7 m) and relative dating using a dynamic programing algorithm allows dating of the full sequence. Elemental data, magnetic properties and beryllium isotopes from Lake Selina reveal a close fit to Antarctic ice core climate proxies. Weaker correlation during the Last Glacial Period (MIS 2–4) is attributed to additional local factors impacting Lake Selina proxies at a time of climate changes and human arrival into Tasmania. Over that period, full vector paleomagne
13 APRIL 2021
The last ice age persisted for over 100,000 years. An ice-bound eternity by any stretch of the imagination, but this long winter was not completely frozen into stillness.
During the Last Glacial Period, which ended approximately 12,000 years ago, climate change existed as a powerful phenomenon, much as it does now, albeit for different reasons.
Over the course of the ice age, a series of abrupt warming episodes punctuated the coldness, each of them sending temperatures soaring (by up to 16 degrees Celsius) in temporary heat waves that flared for decades before disappearing.
These sudden phenomena, called Dansgaard-Oeschger events, took place dozens of times over the 100 millennia of the Last Glacial. But what was it that made them spark to life at all?