Hundreds of millions of years ago, Earth went through two episodes of severe glaciation. These two episodes—the Sturtian and the Marinoan glaciations—occured during the Earth’s Cryogenian Period. The Cryogenian lasted from about 720 million to 635 million years ago.
The phenomenon is called “Snowball Earth” and both instances of it happened in pretty quick succession. And while a planet encased in ice and snow sounds devastating, these episodes may have paved the way for the development of complex life.
The question is, what caused the Earth to freeze over like that?
Continue reading “Did Snowball Earth Happen Because of a Sudden Drop in Sunlight?”
Orbiters are giving us a chance to study the surface of Mars closely, and some of the features that pop to prominence are dry river channels. There are over 10,000 of them. But a new study suggests that glaciers on ancient Mars are responsible for many of them.
According to the study, those glaciers and the water flowing under them are resonsible for carving out some of those riverbeds, rather than free-flowing rivers.
Continue reading “Martian Features Were Carved by Glaciers, not Flowing Rivers”
An iceberg that calved off of from a larger ice formation has spent three years floating on the ocean near Antarctica. The iceberg broke off of the Larsen Ice Shelf in mid-July 2017. It’s been battered and split up into three pieces, but it’s still going.
Continue reading “This Giant Iceberg Has Been Sailing the Southern Seas for Three Years Now”
If—or hopefully when—we cut our Greenhouse Gas (GHG) emissions, we won’t notice much difference in the climate. The Earth’s natural systems take time to absorb carbon from the atmosphere. We may have to wait decades for the temperatures to drop.
Of course, that doesn’t mean we shouldn’t do it. It’s just that we have to temper our expectations a little.
Continue reading “Even If We Cut Greenhouse Gas Emissions Tomorrow, it Would Take Decades for the Earth to Start Cooling Again”
It seems almost certain that an asteroid impact wiped out the dinosaurs. But only almost. Another competing theory won’t completely go away: the extinction-by-volcano theory.
A new study from the UK piles more evidence on the asteroid side of the debate, while adding a new volcanic twist. These researchers say that volcanic activity actually helped life recover from the asteroid strike.
Continue reading “It Was Almost Certainly an Asteroid Impact that Wiped Out the Dinosaurs. In Fact, Volcanoes Might Have Helped Life Recover”
The Antarctic Peninsula is the northernmost part of Antarctica, and has the mildest climate on the continent. In January, the warmest part of the year, the temperature averages 1 to 2 °C (34 to 36 °F). And it’s getting warmer.
Those warm temperatures allow snow algae to grow, and now scientists have used remote sensing to map those algae blooms.
Continue reading “The Coast of Antarctica is Starting to Turn Green”
200 million years ago, a mass extinction event wiped out about 76% of all species on Earth—both terrestrial and marine. That event was called the end-Triassic extinction, or the Jurassic-Triassic (J-T) extinction event. At that time, the world experienced many of the same things as Earth is facing now, including a warming climate and the acidification of the oceans.
A new paper shows that pulses of volcanic eruptions were responsible, and that those pulses released the same amount of CO2 as humans are releasing today.
Continue reading “During Mass Extinction Events, Volcanoes Were Releasing About the Same Amount of CO2 as We Are Today”
On Earth, one of the most important factors regulating our climate is the carbon cycle. This refers to the processes by which carbon compounds are sequestered by biological (photosynthesis) and geological processes and released through volcanic activity and organic processes (decay and respiration). For billions of years, this cycle has kept temperatures relatively stable on Earth and allowed for life to flourish.
For the past few centuries, human activity has tipped the scales to the point that some refer to the current geological epoch as the Anthropocene. According to a new study by an international team of researchers, human activity is also leading to a situation where tropical rainforests (a major sequester of carbon dioxide) are not only losing their ability to soak up carbon but could actually be adding to the problem in the coming years.
Continue reading “As Temperatures Increase, Forests are Having More Trouble Soaking up Carbon”
NASA and the NOAA just announced that 2019 was the second hottest year on record. It barely edged out 2016, the previous warmest year. And both 2019 and 2016 are part of the global warming trend: the last five years have been the warmest five years on record. And the last decade was the warmest decade.
Continue reading “According to NASA, 2019 Was the Second Hottest Year on Record”