The deep sea mining debate grows as demand for rare minerals increases

Episode Transcript

Speaker 1 (00:00):
How Earth's temperature has changed over the past five hundred
million years. Scientists have discovered that Earth's average surface temperature
has fluctuated between eleven and thirty six degrees celsius over
the past five hundred million years. By combining prehistoric temperature
data with climate models, researchers from the Smithsonian National Museum

(00:21):
of Natural History, the University of California, USA, and the
University of Bristol UK created a four hundred eighty five
million year history of Earth's ever changing climate. This new
research was published in Science on September twentieth. Starting the
study in twenty eighteen, the scientists developed a temperature curve

(00:41):
to understand how Earth's climate has changed over the past
five hundred thirty nine million years, a period known as
the Phanerozoic. The idea of creating a robust and reproducible
history of Earth's climate with a comprehensive overview gained a
lot of support, said climate paleontologist and Emily Judd of
the University of Arizona, who join the project in twenty twenty.

(01:05):
To build a deep climate record of Earth using both
geological data and climate models, researchers estimate prehistoric temperatures in
various ways. They examine ice cores that contain trapped air bubbles.
The chemical composition of these bubbles holds clues about the
ancient climate at that time. Oxygen isotopes in prehistoric rock

(01:27):
layers and fossils can also be compared to estimate whether
Earth was warmer or colder during specific periods. Even the
structure of fossilized leaves can serve as temperature indicators. For example,
leaves with smooth edges and long drip tips that allow
water to run off the surface suggest a warm, wet environment,
while plants from colder climates typically have serrated edges and

(01:51):
lack drip tips. Different periods and locations provide different types
of evidence. The first step was to gather all existing evidence.
Along with dozens of paleontology community members, we built a
database with over one hundred fifty thousand estimates of ancient temperatures.
Judd said. The project was published in twenty twenty two.

(02:11):
To build the big picture, collaborators at the University of
Bristol conducted over eight hundred and fifty climate model simulations
for conditions during the Phanerozoic. By combining temperature estimates and
climate models, researchers created a broader view of when ancient
Earth was relatively warmer or colder. The results cover Earth's

(02:32):
temperatures over the past four hundred eighty five million years,
most of the Phanerozoic era, which includes a time marked
by the early explosion of animal life in the oceans,
the appearance of land plants, and several mass extinctions. The
analyzes revealed that Earth's average surface temperature range from eleven
to thirty six degrees celsius during the Phanerozoic, with the

(02:55):
planet generally being much warmer rather than colder. This will
be a very useful record, said climate paleontologist Benjamin Mills
of the University of Leeds in the UK, who was
not involved in the new study. The research not only
improves on previous methods, but also highlights Earth's sensitivity to
carbon dioxide. More research is needed to better understand the

(03:18):
history of that sensitivity. Warm temperatures throughout the past four
hundred eighty five million years were tied to carbon dioxide.
As atmospheric carbon dioxide increased, so did temperatures. This relationship
is particularly evident around certain mass extinctions, when Earth's climate
changed rapidly in response to events like massive volcanic eruptions

(03:41):
that released large amounts of carbon dioxide into the atmosphere.
The stability of global temperatures and CO two levels before
extinctions was important because it was the environment to which
organisms had best adapted, Mills noted. He added that rapid
changes in carbon dioxide and temperature created stressful conditions that

(04:02):
Earth's biodiversity struggled to keep up with the rate of
current climate warming is particularly concerning. The speed of climate
change plays a crucial role in ecological outcomes, Judd said.
Warming that occurs over millions of years forces species to move, evolve,
or go extinct, but adaptation to warmer temperatures is possible.

(04:24):
What humans are doing now resembles moments like the n
Permian mass extinction, when massive volcanic eruptions dumped huge amounts
of carbon dioxide into the atmosphere, leading to the worst
mass extinction event in history. According to jud paying attention
to Earth's temperature is crucial for the survival of human society.

(04:44):
Humanity evolved and thrived under cooler conditions, often near sea
levels that are now being flooded as climate warming causes
sea levels to rise. Earth's resilience doesn't directly translate into
our ability to adapt and thrive in the face of
human caused climate change. According to the research team, Earth
is at a point where any actions limiting human cause

(05:06):
warming are essential