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The following thread of tweets contains a critical evaluation of the NASA page on #ClimateChange.
The FIRST caption on the page is misleading! https://climate.nasa.gov/effects/
The FIRST caption on the page is misleading! https://climate.nasa.gov/effects/
"The potential future effects of global climate change include more frequent wildfires, longer periods of drought in some regions and an increase in the number, duration and intensity of tropical storms."
1. Wildfires are globally decreasing. https://www.earth-syst-sci-data.net/10/2015/2018/
1. Wildfires are globally decreasing. https://www.earth-syst-sci-data.net/10/2015/2018/
Note that there is no general law like:
"Hot and arid conditions cause more wildfires."
There are no wildfires in Sahara.
What is the effect of the greening of Earth on wildfires? I do not know.
We do not know if wildfires will increase. They have been decreasing lately.
"Hot and arid conditions cause more wildfires."
There are no wildfires in Sahara.
What is the effect of the greening of Earth on wildfires? I do not know.
We do not know if wildfires will increase. They have been decreasing lately.
2. Droughts have been decreasing globally (pic).
NASA is wrong to predict more droughts. Why would the decreasing trend change?
Global precipitation did not increase in 1979 - 2014. Why there are less droughts then? I do not know.
https://link.springer.com/article/10.1007/s10712-017-9416-4
NASA is wrong to predict more droughts. Why would the decreasing trend change?
Global precipitation did not increase in 1979 - 2014. Why there are less droughts then? I do not know.
https://link.springer.com/article/10.1007/s10712-017-9416-4
I will tweet later today about the mystery of constant precipitation. There is more humidity in the lower troposphere. Precipitation would increase if convection would remain constant.
Why has convection grown weaker?
Why has convection grown weaker?
3. NASA claims that tropical storms will increase in number and strength.
http://climatlas.com/tropical/
But the actual data shows that has not happened. Why?
Tropical storms are heat engines which convert latent heat in water vapor into mechanical energy of winds.
http://climatlas.com/tropical/
But the actual data shows that has not happened. Why?
Tropical storms are heat engines which convert latent heat in water vapor into mechanical energy of winds.
A heat engine requires something which is warm, or which contains latent heat. It also requires something which is cold.
There is now more water vapor than in 1980. But there might be less "cold" available, because global warming has warmed poles more than the equator.
There is now more water vapor than in 1980. But there might be less "cold" available, because global warming has warmed poles more than the equator.
It is an empirical fact that the 0.5 C of warming in 1980 - 2020 did not change tropical storms appreciably.
NASA is wrong to predict intensification of storms.
Mid-latitude and polar storms are expected to grow weaker. So far, no change is seen in them, either.
NASA is wrong to predict intensification of storms.
Mid-latitude and polar storms are expected to grow weaker. So far, no change is seen in them, either.
"The IPCC predicts that increases in global mean temperature of less than 1.8 to 5.4 degrees Fahrenheit (1 to 3 degrees Celsius) above 1990 levels will produce beneficial impacts in some regions and harmful ones in others."
This is correct.
This is correct.
"Global climate is projected to continue to change over this century and beyond."
Correct.
"Accelerated sea level rise"
Strangely, the acceleration is not evident in many high-quality tide gauges.
The satellite claims that a mountain of water is forming into Western Pacific.
Correct.
"Accelerated sea level rise"
Strangely, the acceleration is not evident in many high-quality tide gauges.
The satellite claims that a mountain of water is forming into Western Pacific.
The New York tide gauge does not show any acceleration.
When will the mountain of water in the Pacific even out?
The sea level is rising only 3 mm per year.
Storms can raise the sea level by 5 meters or more.
3 mm/year is insignificant compared to the natural variability.
When will the mountain of water in the Pacific even out?
The sea level is rising only 3 mm per year.
Storms can raise the sea level by 5 meters or more.
3 mm/year is insignificant compared to the natural variability.
"increases of a month or more in the lengths of the frost-free and growing seasons are projected across most of the U.S. by the end of the century, with slightly smaller increases in the northern Great Plains."
Correct
.
Correct
.
"U.S. suggest that the recent trend towards increased heavy precipitation events will continue. This trend is projected to occur even in regions where total precipitation is expected to decrease"
Correct. Heavy precipitation increased in the Northeast by 40% in 60 years.
Correct. Heavy precipitation increased in the Northeast by 40% in 60 years.
"Droughts in the Southwest and heat waves ... everywhere are projected to become more intense"
Precipitation in the Mediterranean climate zone (California) has been in slight decline. If the trend continues, then droughts will increase modestly in that area.
Precipitation in the Mediterranean climate zone (California) has been in slight decline. If the trend continues, then droughts will increase modestly in that area.
The big question is if global precipitation will start to grow by 2100. That might make the Mediterranean climate more moist.
Sahara was savanna, not a desert, in 9,700 BC to 3,500 BC.
If we are VERY lucky, Sahara can become moist again
.
Sahara was savanna, not a desert, in 9,700 BC to 3,500 BC.
If we are VERY lucky, Sahara can become moist again
.
"Sea Level Will Rise 1-4 feet by 2100"
3 mm/year * 80 years = 24 cm.
According to satellite altimetry and gravimetry, melting ice sheets in Greenland and the Antarctica contribute 40% to the sea level rise.
The ice sheets started to melt considerably only in the 1990s.
3 mm/year * 80 years = 24 cm.
According to satellite altimetry and gravimetry, melting ice sheets in Greenland and the Antarctica contribute 40% to the sea level rise.
The ice sheets started to melt considerably only in the 1990s.
Antarctica was ice-free until 15 million years ago. It started freezing up when polar temperatures were 6 C higher than now.
Greenland was partly ice-free during the Eemian interglacial. Temperatures were 3 C higher.
The big question is what is the new equilibrium state?
Greenland was partly ice-free during the Eemian interglacial. Temperatures were 3 C higher.
The big question is what is the new equilibrium state?
The ice sheets are melting at the edges. They will not melt completely.
It is possible that the ice sheets will find a new equilibrium state where the edges are thinner.
Or the melting will accelerate. If that happens, the sea level rise by 2100 might be much more than 24 cm.
It is possible that the ice sheets will find a new equilibrium state where the edges are thinner.
Or the melting will accelerate. If that happens, the sea level rise by 2100 might be much more than 24 cm.
It would take thousands of years for Greenland to melt completely. For Antarctica, complete melting is impossible.
If Greenland melts 1 meter per year, that will raise the sea level by 5 mm/year.
The sea level rise in 2100 might be as low as 2 mm/year, or up to 10 mm/year.
If Greenland melts 1 meter per year, that will raise the sea level by 5 mm/year.
The sea level rise in 2100 might be as low as 2 mm/year, or up to 10 mm/year.
Raising flood walls by 24 cm - 1 meter by 2100 is not much of a problem.
St. Petersburg in Russia built a huge Kronstadt dam to prevent floods caused by storms in the Gulf of Finland. The 1824 flood was 4.2 meters high.
St. Petersburg in Russia built a huge Kronstadt dam to prevent floods caused by storms in the Gulf of Finland. The 1824 flood was 4.2 meters high.
Summary:
The NASA page starts with a grossly erroneous caption under the photo which shows wildfires, drought, and a hurricane.
After that initial blunder, the page is mostly correct. Surprisingly, NASA even mentions some positive things about #ClimateChange!
The NASA page starts with a grossly erroneous caption under the photo which shows wildfires, drought, and a hurricane.
After that initial blunder, the page is mostly correct. Surprisingly, NASA even mentions some positive things about #ClimateChange!
That was 21 tweets .
If NASA would remove the horrible caption under the first photo, then we could say that the page is informative.
Also, NASA should tell the empirical facts, just like I posted into this thread.
NASA should tell more about uncertainties.
.If NASA would remove the horrible caption under the first photo, then we could say that the page is informative.
Also, NASA should tell the empirical facts, just like I posted into this thread.
NASA should tell more about uncertainties.
