Sixty-Six million years ago a 14 kilometer long, Mount-Everest sized asteroid blasted a hole in the ground, the Chicxulub Impact, releasing the equivalent of 100 million megatons of TNT creating a 20-mile deep, 110-mile hole and sterilizing the remaining 170 million square miles of the ancient continent of Pangaea, killing virtually every species on Earth and, oddly, paving the way for the emergence of the human species.
“As we put more greenhouse gases into the atmosphere and temperatures rise, we are quickly rewinding the climate clock to climate states not seen in human history,” wrote acclaimed University of Wisconsin paleo-climatologist Jack Williams in an email to The Daily Galaxy. “We can expect that over the next few decades, climates will most resemble those of the warm Pliocene, roughly three million years ago, or perhaps even the hothouse Eocene, 50 million years ago.”
“Contrary to our first expectations, global climate was not the primary cause of this change in ocean oxygen and nitrogen cycling,” said biogeochemist Emma Kast currently at the University of Cambridge about the planet’s dramatic increase in oxygen 55 million years ago. The more likely culprit? Plate tectonics. The collision of India with Asia — dubbed “the collision that changed the world” by Columbia University geoscientist Wally Broecker, a pioneer in the ocean’s role in climate change.— closed off an ancient sea called the Tethys, disturbing the continental shelves and their connections with the open ocean.
Recent research has revealed that Venus might have looked like Earth for three billion years, with vast oceans that could have been friendly to life. The early Venusian atmosphere was thinner and the young Sun was emitting less radiation, putting Venus in the habitable zone. There is a real possibility that Venus might have been the first habitable planet in our solar system and radically different from the Venus we see today.
In the blink of a geological eye, nearly 600 million years ago, a massive ice age radically altered the planet’s climate, resulting in a “Snowball Earth,” also known as the Cryogenian Period, severely constricting the oxygen supply on the planet. Scientists at the University of Southampton have proposed that changes in Earth’s orbit may have allowed complex life to emerge and thrive during the most hostile climate episode the planet has ever experienced.
“Our models show that there is a real possibility that Venus could have been habitable and radically different from the Venus we see today,” said Michael Way of The Goddard Institute for Space Science about Earth’s ‘twisted sister’ planet. “This opens up all kinds of implications for exoplanets found in what is called the ‘Venus Zone’, which may in fact host liquid water and temperate climates.”