5 thoughts on “DeGrasse Tyson: “We Are Witnessing The ‘Unraveling Of An Informed Democracy'””
Tyson, 1:25: “Generally, when we think of weather we don’t think of clear blue skies we think of what WATER is doing in the atmosphere. Is it snow, sleet, hail, rain, wind-driven? When we think of ‘weather’ that’s what we think of. And so, when you store that much more moisture in the atmosphere, we are that much more susceptible to the extremes of weather. So a storm would be more intense, droughts would be more intense, and so these [hurricanes] are shots across our bow.”
That’s insightful, and could be helpful in describing to the general public how climate change will change the weather. The old Charles Dudley Warner complaint goes “Everybody complains about the weather, but nobody does anything about it”. But, really, we DID do something about it: we made it worse (through higher moisture content).
That’s an interesting way of looking at it, but we at least have the good fortune not to be living during the time of the next 10 to 100 generations (assuming they happen), when what water is doing will only be part of the story. We in the US will have (as some people do now) weather reports from California to Ohio and Mexico to Montana, that include updates on what dust and sand are doing, and crucial, life and death information on what the wind speed is, and warnings on what the temperature is so you know if you can go outside long enough to take the trash out without dying.
Also at 6:25…he explains how incremental changes at storm surges will catch up with us. Overtop the levee and flood the city, so you move the city inland, then again at the next instance. He also reminds us that insurance companies and the military — organizations that understand risk better than any — are well aware of this.
Thresholds of catastrophe in the Earth system
Daniel H. Rothman
Science Advances 20 Sep 2017:
Vol. 3, no. 9, e1700906
DOI: 10.1126/sciadv.1700906
Abstract
The history of the Earth system is a story of change. Some changes are gradual and benign, but others, especially those associated with catastrophic mass extinction, are relatively abrupt and destructive. What sets one group apart from the other? Here, I hypothesize that perturbations of Earth’s carbon cycle lead to mass extinction if they exceed either a critical rate at long time scales or a critical size at short time scales. By analyzing 31 carbon isotopic events during the past 542 million years, I identify the critical rate with a limit imposed by mass conservation. Identification of the crossover time scale separating fast from slow events then yields the critical size. The modern critical size for the marine carbon cycle is roughly similar to the mass of carbon that human activities will likely have added to the oceans by the year 2100.
From the Forbes article
The upside? The effects of this mass extinction event will take a while to be fully realized. While we have increased the amount of carbon at unprecedented rates, it takes the Earth some time to equilibrate to the new conditions. This means we have thousands of years (a blip in the geologic record) for the mass extinction to fully be in effect.
The downside? The basis of how long extinction events take to fully realize is based on past extinction events. And just as we discussed above, none of those previous extinction events saw carbon increase on the order of hundreds of years. So, long story short, we can’t fully know what is in store for the future.
As geologists, we look to the past to understand the future. Unfortunately, we’re in a transformative time in Earth’s history where things are changing faster than they ever have in the past. That makes predicting the future much harder, something that worries scientists. And should worry you.
Tyson, 1:25: “Generally, when we think of weather we don’t think of clear blue skies we think of what WATER is doing in the atmosphere. Is it snow, sleet, hail, rain, wind-driven? When we think of ‘weather’ that’s what we think of. And so, when you store that much more moisture in the atmosphere, we are that much more susceptible to the extremes of weather. So a storm would be more intense, droughts would be more intense, and so these [hurricanes] are shots across our bow.”
That’s insightful, and could be helpful in describing to the general public how climate change will change the weather. The old Charles Dudley Warner complaint goes “Everybody complains about the weather, but nobody does anything about it”. But, really, we DID do something about it: we made it worse (through higher moisture content).
That’s an interesting way of looking at it, but we at least have the good fortune not to be living during the time of the next 10 to 100 generations (assuming they happen), when what water is doing will only be part of the story. We in the US will have (as some people do now) weather reports from California to Ohio and Mexico to Montana, that include updates on what dust and sand are doing, and crucial, life and death information on what the wind speed is, and warnings on what the temperature is so you know if you can go outside long enough to take the trash out without dying.
Also at 6:25…he explains how incremental changes at storm surges will catch up with us. Overtop the levee and flood the city, so you move the city inland, then again at the next instance. He also reminds us that insurance companies and the military — organizations that understand risk better than any — are well aware of this.
Very interesting paper, Forbes has a good precis and analysis
MIT Professor Predicts Earth’s Next Mass Extinction To Begin By 2100
The paper
http://advances.sciencemag.org/content/3/9/e1700906
Thresholds of catastrophe in the Earth system
Daniel H. Rothman
Science Advances 20 Sep 2017:
Vol. 3, no. 9, e1700906
DOI: 10.1126/sciadv.1700906
Abstract
The history of the Earth system is a story of change. Some changes are gradual and benign, but others, especially those associated with catastrophic mass extinction, are relatively abrupt and destructive. What sets one group apart from the other? Here, I hypothesize that perturbations of Earth’s carbon cycle lead to mass extinction if they exceed either a critical rate at long time scales or a critical size at short time scales. By analyzing 31 carbon isotopic events during the past 542 million years, I identify the critical rate with a limit imposed by mass conservation. Identification of the crossover time scale separating fast from slow events then yields the critical size. The modern critical size for the marine carbon cycle is roughly similar to the mass of carbon that human activities will likely have added to the oceans by the year 2100.
From the Forbes article
The upside? The effects of this mass extinction event will take a while to be fully realized. While we have increased the amount of carbon at unprecedented rates, it takes the Earth some time to equilibrate to the new conditions. This means we have thousands of years (a blip in the geologic record) for the mass extinction to fully be in effect.
The downside? The basis of how long extinction events take to fully realize is based on past extinction events. And just as we discussed above, none of those previous extinction events saw carbon increase on the order of hundreds of years. So, long story short, we can’t fully know what is in store for the future.
As geologists, we look to the past to understand the future. Unfortunately, we’re in a transformative time in Earth’s history where things are changing faster than they ever have in the past. That makes predicting the future much harder, something that worries scientists. And should worry you.