“Venus is like Earth in so many ways,” explained Stephen Hawking, who is now buried in Westminster Abbey next to Issac Newton and Charles Darwin. “A sort of kissing cousin. She’s almost the same size as Earth, a touch closer to the Sun. And, she has an atmosphere that could crush a submarine.” In the original documentary series Stephen Hawking’s Favorite Places, the renowned physicist proposed that climate-science deniers take a trip to Venus, offering to pay for their fare to view the ultimate planetary results of their ignorance.
On October 9, 2018 Pulitzer-Prize winning journalist, Eugene Robinson of the Washington Post wrote: “Here is how to interpret the alarming new United Nations-sponsored report on global warming: We are living in a horror movie.”
The conditions on Venus today, Hawking said, are almost impossible to comprehend. Planetary scientists say “start by imagining Hell and work up from there.” At the surface, Venus roasts at more than 800 degrees Fahrenheit under a suffocating blanket of sulfuric acid clouds and a crushing atmosphere more than 90 times the pressure of Earth’s that has flat-out crushed every probe we’ve sent to it.
According to the Intergovernmental Panel on Climate Change (IPCC), Robinson refers to, the impact of human-induced warming is worse than previously feared, the report released Monday says, and only drastic, coordinated action will keep the damage short of catastrophe.
Intelligent speculation on climate’s unknown unknowns is sorely needed by policymakers, observes William B. Gail, past president of the American Meteorological Society, in today’s New York Times. “Most of these smaller environmental changes should be manageable, he writes,”readily addressed through adaptation. Inevitably, however, a rare few will most likely evolve and expand until they threaten our security, health or economy. We lack the ability to predict which are which. This is the curse of unknown unknowns. Nevertheless, things we can credibly imagine should accentuate our concern for what we are unable to imagine.
“Perhaps a routinely ice-free Arctic summer, altering polar ocean life in subtle ways, sets off an unpredictable cascade of complex changes throughout the global ocean ecosystem, devastating fisheries,” Gail continues. “Maybe agricultural pests adapt to climate change stresses by evolving novel and frequently changing abilities to destroy crops, leaving farmers struggling to keep pace and feed populations. One unsettling risk is that mutant diseases — like Zika and Ebola today and the 1918 flu epidemic that killed 50 million people — could emerge more often because of altered evolutionary competition in a changing climate, each a greater medical challenge than the last.”
Some threats might be so startling and strange that our imaginations would struggle to comprehend them even after they arise. Timely response efforts would be frustrated by poor knowledge about what is occurring and how to contain the threat.
To this point, climate change has been a slow-motion calamity whose impacts, month to month and year to year, have been hard to perceive. Unfortunately, according to the report, that is about to change.
The burning of fossil fuels on an industrial scale has raised global temperatures by about 1.8 degrees Fahrenheit. That may not sound like much, but look at the consequences we’re already seeing: Stronger, slower, wetter tropical storms. Unprecedented heat waves. Devastating floods. Dying coral reefs. A never-before-seen summer shipping lane across the Arctic Ocean.
Meanwhile, humankind continues to pump heat-trapping carbon dioxide into the atmosphere at a tragically self-destructive rate. The IPCC calculates that a further temperature rise of 1.5 degrees Celsius — almost inevitable, given our dependence on coal, oil and gas — would be challenging but manageable. An increase of about 2 degrees, however, would be disastrous.
In the findings of a study conducted by the National Aeronautics and Space Administration (NASA) in 2002, it was suggested that Venus shared similar traits to the Earth and even had water around 4.5 billion years ago. However, as the planet increasingly warmed, more water vapor was in its atmosphere resulting to more heat being trapped which continued until its oceans completely evaporated.
Using rudimentary computer-generated imagery (CGI), Hawking can be seen traveling in a spaceship to Venus as he passed through clouds of sulfuric acid. However, he finds that the pressure on the planet is roughly 90 times that of the Earth “enough to crush a submarine,” while the temperature is around 200 degrees. He explains that the Earth could find itself in a similar situation if greenhouse gases are not controlled.
Venus was created at about the same time as Earth, in about the same place, and it’s roughly the same size – it would therefore have started with the same materials as us, drawn together from the same region of the planet forming dust left over from the sun. But Venus now has only 0.001% of our water content, and a couple of flybys by the Venus Express may have revealed the reason.
In 2008, the probe discovered hydrogen and oxygen streaming off the night side of the planet in a 2:1 ratio, whicyou might recognize as the ratio in H20. It seems that what little water Venus has left is being blasted apart in the atmosphere by the solar wind, a vast stream of charged particles blown out by the sun. Venus Express has passed by the dayside and measured almost three hundred kilograms of hydrogen a day being lost into space. It hasn’t found any oxygen yet, but the search continues.
“Venus today has a thick atmosphere that contains very little water, but we think the planet started out with an ocean’s worth of water,” said John T. Clarke of Boston University.
Scientists are still trying to determine whether water existed on the surface of Venus or only high up the atmosphere, where temperatures were cooler. If the surface temperature stayed below the boiling point of water long enough, rivers might have once flowed on the planet. Venus may have even had ice.
The key to figuring out how much water Venus once had lies in how much hydrogen and deuterium, a heavier version of hydrogen, remain in the atmosphere. Both can combine with oxygen to make water, either in the familiar H2O form or the rarer hydrogen, deuterium and oxygen form, called HDO. (Very small amounts of D2O also form.)
Intense UV light from the sun has broken apart nearly all of the water molecules in Venus’ atmosphere. Because he regular hydrogen atoms in the water are lighter, they escape into space more quickly than the heavier deuterium ones. By comparing the amount of deuterium now in the atmosphere to the amount of hydrogen, researchers can estimate how much water disappeared from Venus and how quickly it happened.
Early estimates, made from data collected by NASA’s 1978 Pioneer Venus spacecraft and other observations, indicated Venus could have had enough ancient water to cover the entire planet with 23 feet (7 meters) of liquid. But it turns out that the amounts of hydrogen and deuterium can vary at different heights in Venus’ atmosphere, which could change the calculations.
Data gathered from European Space Agency’s Venus Express is invaluable to climate scientists modeling Earth’s climate to predict its future. Astrobiologist David Grinspoon believes that scientists should look at our neighboring planets to help understand the perils of global warming.“It seems that both Mars and Venus started out much more like Earth and then changed. They both hold priceless climate information for Earth.”
Climate scientists believe that Venus experienced a runaway greenhouse effect as the Sun gradually heated up. Astronomers believe that the young Sun was dimmer than the present-day Sun by 30 percent. Over the last 4 thousand million years, it has gradually brightened. During this increase, Venus’s surface water evaporated and entered the atmosphere.
“Water vapor is a powerful greenhouse gas and it caused the planet to heat-up even more. This is turn caused more water to evaporate and led to a powerful positive feedback response known as the runaway greenhouse effect,” says Grinspoon.
As Earth warms in response to manmade greenhouse gases, it risks the same fate. Reconstructing the climate of the past on Venus can give scientists a better understanding of how close our planet is to such a catastrophe. However, determining when Venus passed the point of no return is of vital importance.
“Though climate change has yet to produce clearly attributed examples,” observes Dr. Gail, “Zika hints at this dispiriting future. Within a few short years, it transformed from an ignorable rare disease into a medical terror. Nobody saw it coming. Its long-term societal consequences run deep, with childbearing upended for people threatened by the mosquito that carries the virus. Though probably not a direct result of climate change, Zika starkly illustrates the type of inconceivable surprises, and their demoralizing consequences, that threaten to emerge with ever greater frequency should we fail to slow global warming.”
A image of the Venus at the top of the page as it was seen by the Japanese probe Akatsuki. The clouds of Venus could have environmental conditions conducive to microbial life. (Japan Aerospace Exploration Agency)