Climate Change

[Arden Portis]

The measures needed to address climate change in any meaningful capacity would require the economic, political and social domination of white supremacy to pretty much be turned on it's head. And it would probably take nothing less than a significant number of the "right kind of people" dying as a direct and undeniable result of climate change in order for that to happen. 

By then, it will probably be too late.

[Kaneda]

The measures needed to address climate change in any meaningful capacity would require the economic, political and social domination of white supremacy to pretty much be turned on it's head. And it would probably take nothing less than a significant number of the "right kind of people" dying as a direct and undeniable result of climate change in order for that to happen. 

By then, it will probably be too late.

I’m sure you mean well, but I should let you know that I’ve engaged in this kind of discussion and encountered this thought-terminating cliché many times before.

So much so, that whenever I see a comment end in some variation of “it will already be too late,” I don’t even bother reading the rest.

[Arden Portis]

The measures needed to address climate change in any meaningful capacity would require the economic, political and social domination of white supremacy to pretty much be turned on it's head. And it would probably take nothing less than a significant number of the "right kind of people" dying as a direct and undeniable result of climate change in order for that to happen. 

By then, it will probably be too late.

I’m sure you mean well, but I should let you know that I’ve engaged in this kind of discussion and encountered this thought-terminating cliché many times before.

So much so, that whenever I see a comment end in some variation of “it will already be too late,” I don’t even bother reading the rest.

Well it's not simply a cliché, it's reality. The dismantling of that system to a significant degree it is what it will take effect change.
And the powers that be who uphold that system are not going to be willing to take that L unless it comes down their survival.

If folks aren't up to acknowledging the root cause of the problem, and instead wish to chastise those who do and/or rail on ordinary citizens for not "doing their part" and not pretending that climate change isn't a matter that is well beyond their control, then oh well. It's to be expected.
Recognizing that reality doesn't allow much room for the illusion of control, so it's perfectly understandable that people get bent out of shape about it and/or dismiss it.

Anyway, I was just weighing in with my thoughts. They weren't directed at you in particular.
Heck, I don't even know you. 

So no offense, but it really doesn't matter to me if you read what I write or not.

[Alan V]

Climate Change Summarized

Section 1: How we know climate change is happening

Global warming and climate change

Global warming refers to the gradual increase in the global average surface temperature. Since the earth is so vast, the increase of even a few degrees represents an immense amount of heat captured in the atmosphere. Global warming causes climate change, and the more heat captured, the more the climate changes. Climate change affects not only the atmosphere but also the cryosphere (ice), the hydrosphere (the water cycle), and the biosphere (life).

Climate versus weather

Climate is statistically average weather over long periods of time. Weather is often chaotic, which is why it can be predicted with only moderate accuracy in the short term. Climate is not chaotic, which means climate can be predicted with fair accuracy far into the future. It’s like the difference between forecasting if it will rain tomorrow and projecting if it will be hot next summer.

The assumption that climate is equal to weather has caused any number of confusions. No one can tell just by observing local weather events if the global climate is changing or not. Only scientists with a wide range of available information can perform the statistical analyses required to say if the climate is changing and to what degree it is affecting the weather.

Temperatures are rising

The global average surface temperature has risen 1.0̊C (1.8̊F) since 1880. Scientists typically refer to the temperature change caused by global warming as being compared with the preindustrial average. Most of that temperature rise has been within the last 35 years. Every part of the world is affected, though at different rates. In general, temperatures are rising twice as fast at the poles than the average for the rest of the planet. Average temperatures are also rising about twice as fast over the land than over the ocean because of evaporation and the depth of the water. Nevertheless, around 93% of all global warming is absorbed by the oceans. Because so much of the heat of global warming accumulates at the poles and in the oceans, it is not observed except by scientists who monitor temperatures worldwide.

The 2000s have seen more than twice as many record highs as record lows. Heat waves are becoming more frequent and cold snaps are shorter and milder. As of 2010, spring was arriving on average 10 days to 2 weeks earlier than in 1990. Flowers, birds, and other species are moving toward the poles and up mountains to maintain their optimal environments.

Each decade since the 1980s has been warmer than the last. Most of the hottest years on record occurred in the last two decades. The tropics are expanding. Temperatures will continue to rise because the earth is not in thermal equilibrium. The planet is presently warming at a rate of nearly 0.2̊C (0.36̊F) every decade, but may increase that rate of change in the future.

[Alan V]

Ice is melting

The cryosphere includes the ice cap over the waters of the Arctic, the ice sheets covering Greenland and Antarctica, the mountain glaciers on most continents, and the permafrost of the northern areas of North America, Europe, and Asia.

Arctic sea ice has lost three-quarters of its volume and half of its area in the past 30 years. The Greenland and Antarctic ice sheets are losing a total over 400 billion tons of ice per year. Glacier melting and movement in Greenland and Antarctica is accelerating. The rate of Antarctic ice loss has tripled in the last decade.

In the late 1880s, Glacier National Park had 150 glaciers. Now about 25 smaller glaciers are left, and may disappear by 2030. Mountain glaciers are similarly retreating around the world. The permafrost is also thawing in some areas, leading to “drunken forests” and the damage of infrastructure built on the changing soils.

Sea levels are rising

Since 1880, sea levels have risen an average of 8 inches. Sea levels are currently rising 0.12 inch per year, but this is also accelerating. 1/3 of present sea level rise is caused by the thermal expansion of warming oceans and 2/3 from melting ice.

[Alan V]

Extreme weather events are becoming more frequent

Warmer air can hold more moisture and is generally more humid. Overall rainfall has increased 2 to 3% so far, but extreme rainfall has increased 7%. This means we are already seeing heavier rainstorms in the summer and bigger snowstorms in the winter. Precipitation increases cause more flooding.

Further, changing temperatures alter precipitation patterns. Precipitation increases in some places and decreases in others. In the United States, the Northeast has been wetter, but the Southeast has been dryer and the Southwest much dryer. Typically, wet areas have been getting wetter and dry areas dryer.

With a warmer climate, evaporation increases and causes more drought. Since the 1970s, droughts last longer, are more intense, and are spreading over larger areas. Similarly, heat waves are lasting longer. Fire frequency and area in the western United States have both increased greatly over the past several decades. This is largely due to climate change, but forest management and freshwater use are also factors.

With the Arctic warming faster than other areas, Arctic air is drifting southwards into the jet stream. As a result, the jet stream is slowing so that big bends reach even farther south and are locked in for more days than usual. The results are more days of extreme cold or warmth during winter months.

There has been an increase in category 4 and 5 hurricanes since 1970. Hurricanes feed off warm ocean waters, so warmer waters increase hurricane intensity and rainfall. Higher sea levels increase storm surges as well. Hurricanes can also form further north and south, but so far scientists are unsure whether global warming increases or decreases the total number of hurricanes.

Researchers are getting better at using attribution science to understand the extent to which global warming is affecting single events. However, all weather events are affected by global warming, since the climate is warmer and moister than it was before. Extreme weather is becoming the new normal.

Scientific observations

Because figuring the global average surface temperature requires measurements from around the world, it is no simple task. To make their comparisons, scientists have recorded the earth’s surface temperature at widespread locations since about 1880. Presently a handful of organizations monitor temperatures at thousands of locations worldwide. This is why no ordinary person in any one place can say whether global warming is occurring or not.

Researchers publish thousands of papers on climate science each year. Globally, several billion dollars are spent annually on climate change research, employing thousands of scientists in many countries, including climatologists, chemists, meteorologists, oceanographers, physicists, and other specialists. NASA and the European Space Agency both have satellites recording the steady retreat of ice sheets and the steady rise of sea levels. NOAA employs underwater drones, buoys, and shipborne instruments to record ocean carbon levels and temperatures. None of this is easy, so each of the above observations represents huge amounts of collected information.

[Alan V]

Section 2: How we know people are causing present climate change

Questions

Of course, all of these observations do not answer several very important questions, and in answering them climate science gets much more complicated. What are the causes of the changes? Are such causes human, natural, or a combination of both? How much of the problem can be attributed to each cause? Are the causes temporary? To answer these questions, we need to understand a few points about natural climate change.


Proxies

Direct scientific observations go back only so far. To extend their picture of past climates on the earth, scientists use a range of proxies which together form a consistent picture of what the earth’s climate was like in different eras. Such proxies include ancient ice, fossils, tree rings, pollen, corals, stalagmites, glacial debris, volcanic rock, and lake and ocean sediments. For instance, carbon dated fossils show what could live where, grains of pollen in lake sediments show whether pines or maples grew at certain times, tree rings capture temperature information since trees grow better in warm temperatures, and so on. Scientists can tease out all sorts of information from these proxies through their careful detective work.

Most important for climate change have been ice core samples from Greenland and Antarctica, which capture oxygen and carbon dioxide from as long as 800,000 years ago in bubbles frozen in the ice. From oxygen isotopes, scientists can determine temperatures. From CO2, they can tell how many parts per million (ppm) accumulated in past atmospheres. Comparing the information from both has shown that temperatures and CO2 concentrations are highly correlated. Whenever there is a high concentration of CO2 in the atmosphere, the world is warm; when there is a low concentration, the world is cold and icy.

[Alan V]

Past climate change

Piecing together all of this information, scientists have learned that over billions of years the earth has gone through remarkable swings in its climate, from being nearly tropical from pole to pole to being frozen almost all the way to the equator. However, most of such extremes were caused by conditions which are no longer present on the earth, like extremely high levels of CO2 caused by extreme volcanism, or different water circulation patterns caused by the different locations of the continents.

Not surprisingly, past sea levels have been much lower or much higher with changes in temperatures, since the ice sheets melt or accumulate again depending on those temperatures. According to paleoclimatology, the study of ancient climates, the sea level has varied from over 200 feet higher to 400 feet lower.

How much our present ice sheets melt, and how high our sea levels rise, will depend on how much the global average temperature rises. It nevertheless may take hundreds of years for them to stop melting even after temperatures stabilize. That’s why it’s important for us to know how much they rose in the distant past at certain temperatures, when they were at an equilibrium. So for instance, if the temperature rises to 2̊C or more over the preindustrial, that would be as warm as in the Pliocene 3 million years ago, when the sea level was 50 to 80 feet higher.

Chemical weathering

The primary reason the earth has been ice-free for most of its history was because of much greater concentrations of CO2 in the atmosphere. Between 300 and 34 million years ago, there were no large ice sheets anywhere. However, previously large concentrations of CO2 have slowly been reduced, over very long periods of time, by a process called chemical weathering. The uplift of the Himalayan Mountains is considered the cause for the cooling trend over the past tens of millions of years. So the earth has gradually cooled since 50 million years ago, the ice sheet over Antarctica dates from about 35 million years ago, and the Arctic froze permanently about 3 million years ago.

The chemical weathering of rocks removes CO2 from the atmosphere. This has worked as a thermostat on the earth’s temperature, since weathering increases with more CO2, warmer temperatures, and increased rainfall, and decreases with less CO2, colder temperatures, and decreased rainfall. Plant life also typically acts as a brake on CO2 levels. However, the process of chemical weathering is far too slow to restore the earth’s natural balance in the short run.

[Alan V]

Natural climate change

In the last 2.7 million years or so, there have been dozens of glacial-interglacial cycles. So the natural pattern of climate change over that period has been one of long ice ages separated by shorter warm periods. It takes tens of thousands of years for the earth to cool down, but only a few thousand to warm again. We are presently living in such a warm period called the Holocene, which started after the last ice age ended around 12,000 years ago.

Scientists are convinced that these natural climate changes can be explained by small shifts in the earth’s orbit, the Milankovitch cycles, which increase or decrease the solar energy it receives. The earth’s axis, the precession of the equinoxes, wobbles on a 23,000 year cycle. The earth’s tilt shifts on a 41,000 year cycle. And the earth’s eccentricity, how elliptical its orbit is, oscillates on a 100,000 year cycle. The 100,000 year cycle has the greatest impact on global average temperatures. Presently, the first two cycles are out-of-phase by about 10,000 years and the orbital eccentricity is small, so the length of our interglacial period would normally be extended beyond the typical. The last time the earth was in this configuration 400,000 years ago, the interglacial was 50,000 years long.

These variations are amplified by the increase or decrease of CO2 which follow them by several hundred years. Soils and oceans release or capture CO2 and methane depending on their temperatures, so both rise and fall in close correlation with the ice age cycles, amplifying their climate extremes. These greenhouse gases account for nearly half the glacial-interglacial global temperature changes. This correlation goes back 650,000 years, through seven glacial cycles.

This is the natural climate change we could expect if no other factors came into play. Nevertheless, present climate change will likely delay the onset of the next ice age for over 130,000 years. CO2 has varied between 180 and 290 ppm for hundreds of thousands of years. It was 280 ppm as late as 1750, before the industrial revolution. But at over 405 ppm today, it is about 45% higher, and likely the highest it has been for millions of years.

Natural variability

Overlaying that general pattern of glacial and interglacial periods is a fair amount of natural variation.

Weather is chaotic, so it varies in ways which have nothing to do with the overall trends of climate. Different factors cause this natural variability, and those factors must be taken into account and averaged out, or even offset in some cases, to clearly see the overall trends in climate. Such factors include the El Niño Southern Oscillation for instance, or volcanic eruptions, increases in industrial aerosols like after the end of World War II, and temporary changes in solar output. Some variations are regional rather than global, which must also be taken into account.

The average temperature varies randomly above and below the trend line by about 0.2̊C, or about 0.4̊F. Volcanic particles lifted into the stratosphere can lead to a cooling effect which lasts for two or three years on average, followed by a slow recovery. Solar output varies by about 0.1% over the typical ten-to-twelve year solar cycle. Although no unexpected, large solar output variations have happened in the near past, further back in history they led to such events as the Medieval Warm Period and the Little Ice Age, according to solar proxies.

The warming caused by increased CO2 in the atmosphere can be masked by such natural variability by as long as a decade or more, which is why long-term tracking of weather is so important in detecting climate change. For instance, a recent apparent pause in the upward trend of global warming temperatures was caused by a combination of volcanic activity, a short-term reduction in solar output due to the natural solar cycle, and a series of La Niña events. The background “noise” of natural variability must be taken into account to clearly see the steady “signal” of incrementally increasing temperatures. This is why natural variability was still considered a possible explanation for observed changes as late as the 1990s.

[jerryg]

I think the climate change 'side' would benefit from getting on the same page. They spend a lot of time arguing whether or not climate change is real with the stupidest people.

What people need is when and how much. Is New York going to be underwater in 2050? Are we going to be extinct by 2100? Is it reversible? Are we going to need to Thanos the place to survive? Because the climate change people have been setting out all these deadlines for decades. And then they pass, and they're like, well...maybe if we do this...we have until such and such date instead.

The threat to our future remains abstract. And it's unclear whether the solutions are in fact solutions, things that'll buy us another decade, or just spitting into the wind. These are what people need to hear to become invested.

[Alan V]

What people need is when and how much.  Is New York going to be underwater in 2050?  

No, but Miami and New Orleans may be by 2100.  I will get to these and other specifics as I continue to post my paper.

Are we going to be extinct by 2100?  

No, but 50% of species could be committed to extinction by then if we continue with a business-as-usual emissions scenario.

Is it reversible?  

Not for hundreds of years, unless we invest heavily in carbon capture and storage technologies to reduce the amount of CO2 in the atmosphere.

Are we going to need to Thanos the place to survive?  

No, but population is obviously one of the multiplying factors of climate change: I = PAT.  In other words, the environmental impact equals the population times the affluence times the technology.  Cleaner technologies will likely be our best solution, since our population will remain high for decades to come, and only some people will want to change their affluence (how much they travel, how much beef they eat, and so on).

Because the climate change people have been setting out all these deadlines for decades.  And then they pass, and they're like, well...maybe if we do this...we have until such and such date instead.

The actual projections of scientists have been largely accurate, with the obvious exception of how fast the ice sheets would melt.  They are melting much faster than scientists estimated in their models -- if I remember correctly, 60% faster.

The threat to our future remains abstract.  And it's unclear whether the solutions are in fact solutions, things that'll buy us another decade, or just spitting into the wind.  These are what people need to hear to become invested.

Yep.  I couldn't agree more.  That's why I read and took notes from over 50 books on various aspects of climate change, summarized it all in 42 pages, and have begun posting my paper in this forum. I evaluate the potentials of possible solutions in one section, which I will likely post a few paragraphs at a time later this month, or perhaps next month.

[Alan V]

The natural carbon cycle

The sources of CO2 in the atmosphere were in a natural balance for centuries. The carbon which was released into the atmosphere by natural processes was reabsorbed by other natural processes at almost exactly the same rate. CO2 was exchanged between the atmosphere, oceans, animals, and plants through gas exchange, volcanic eruptions, respiration, decomposition, and photosynthesis.

Sinks and sequestration

The earth possesses many natural carbon sinks in which it sequesters huge amounts of carbon, much more than is in the atmosphere. These include the peatlands, the biosphere, the permafrost, the oceans, and especially carbonate rocks. Our modern problem is that we have been digging up carbon in coal, oil, and natural gas from underground where it was safely sequestered, and releasing a great amount of that carbon as CO2 into the atmosphere.

The greenhouse effect

Our atmosphere is 78% nitrogen and 21% oxygen. Both are transparent to visible and infrared light. The sun shines mostly visible light, and the earth reflects mostly infrared light. Even in trace amounts, the more complex molecules of the greenhouse gases are transparent to the incoming visible light but partly opaque to the reflected infrared, and therefore trap heat in the lower atmosphere. Natural concentrations of greenhouse gases are the reason the average global surface temperature is 59̊F rather than 3̊F. In other words, the earth would be frozen to the equator without greenhouse gases in its atmosphere.

[Alan V]

Greenhouse gases

Certain gases are well-known to physicists to be heat-trapping gases. To compare the heating potential of these gases, each is given a CO2 equivalent (CO2e) value, or a comparison with the heating potential of CO2 which is assigned the value of 1. Global warming potential equals the potency (CO2e) times the volume in the atmosphere times the residence time in the atmosphere.

Carbon dioxide (CO2) is emitted from fossil fuel burning, cement making, logging and burning forests, and tilling the soil. Although it is one of the weaker greenhouse gases, the fact that we are pouring such great quantities into the atmosphere, and that it can remain there for hundreds of years, makes it of the greatest concern.

Methane (CH4) is emitted from the production and transport of natural gas, raising livestock, decaying landfills, and agriculture. For instance, bacteria in flooded rice paddies produce methane. The average lifetime of methane in the atmosphere is 12 years, but it oxidizes into CO2 which remains much longer. Methane is 86 CO2e over 20 years, and 34 CO2e over 100 years. The methane concentration in the atmosphere is now at two and a half times the preindustrial level, but its concentration is several hundred times lower than CO2.

Nitrous oxide (N2O) is emitted from agricultural fertilizers, burning fossil fuels, industrial processes, and solid waste. It remains in the atmosphere for 121 years on average, is broken down by sunlight, and is 298 CO2e in a 100 year period. N2O is up 15% since 1750, but its concentration is also low.

Tropospheric ozone (O3) only remains in the atmosphere for 50 days.

Fluorocarbons (CFCs and HFCs) remain in the atmosphere for over 1000 years, and are many times more powerful than CO2, but are emitted in trace amounts. HFCs are 1000 to 9000 CO2e, depending on the chemical composition. All are produced by humans.

Water vapor (H2O) is the most abundant – about 10 times more than CO2 – and powerful greenhouse gas, but it only stays in the atmosphere for an average of 9 days before it washes out. However, water vapor is nevertheless a very powerful feedback. As the earth warms from other greenhouse gases trapping heat, more water evaporates and remains in the atmosphere, amplifying the heating.

Black carbon and deforestation

Black carbon is 7 to 15 billion tons CO2e per year. Approximately 42% comes from outdoor fires; 25% from burning wood, coal, dung, and peat in homes; 25% from transport, mainly diesel; and 10% from coal-fired power. Black carbon particulates only spend 8 to 10 days in the atmosphere, but are continually emitted, so they are the second largest driver of climate change after CO2 according to some researchers. They absorb heat in the atmosphere, on the ground, and on snow and ice which increases their rate of melting.

Similarly, forest fires and deforestation for agricultural purposes not only contribute to black carbon but destroy carbon sinks useful for sequestration of carbon.

Man’s contributions

Human induced positive forcings include the greenhouse gases, ozone, and black carbon aerosols. Negative forcings include reflective aerosols and aerosol cloud changes.

Although the question of whether the accumulated results of human actions causes climate change is still controversial for some people, the matter is considered settled science by an overwhelming number of experts. This is because the argument for man-made climate change is very simple. First, greenhouse gas concentrations in the atmosphere are measurably increasing. Atmospheric concentrations of CO2 have risen from 280 ppm preindustrial to over 405 ppm today. Second, these increased concentrations lead to a general warming of the earth. The physics is well-established. Third, the climate is changing. Careful scientific observations over long periods of time has established this to be true. Fourth, humans are responsible for almost all of those greenhouse gas emissions as is verified by the scientific fingerprint analysis of multiple possible causes. Humans produce more than 36 billion tons of CO2 pollution per year. Deforestation is responsible for 10% to 15% of that excess CO2.

Because of increasing demand for fossil fuels in the developing world, CO2 emissions are presently still increasing rather than leveling off or declining. Energy use is responsible for 70% of greenhouse gas emissions. Agriculture and other land-use is responsible for 30%.

[Yonadav]

What people need is when and how much.  Is New York going to be underwater in 2050?  

No, but Miami and New Orleans may be by 2100.  I will get to these and other specifics as I continue to post my paper.

Are we going to be extinct by 2100?  

No, but 50% of species could be committed to extinction by then if we continue with a business-as-usual emissions scenario.

Is it reversible?  

Not for hundreds of years, unless we invest heavily in carbon capture and storage technologies to reduce the amount of CO2 in the atmosphere.

Are we going to need to Thanos the place to survive?  

No, but population is obviously one of the multiplying factors of climate change: I = PAT.  In other words, the environmental impact equals the population times the affluence times the technology.  Cleaner technologies will likely be our best solution, since our population will remain high for decades to come, and only some people will want to change their affluence (how much they travel, how much beef they eat, and so on).

Because the climate change people have been setting out all these deadlines for decades.  And then they pass, and they're like, well...maybe if we do this...we have until such and such date instead.

The actual projections of scientists have been largely accurate, with the obvious exception of how fast the ice sheets would melt.  They are melting much faster than scientists estimated in their models -- if I remember correctly, 60% faster.

The threat to our future remains abstract.  And it's unclear whether the solutions are in fact solutions, things that'll buy us another decade, or just spitting into the wind.  These are what people need to hear to become invested.

Yep.  I couldn't agree more.  That's why I read and took notes from over 50 books on various aspects of climate change, summarized it all in 42 pages, and have begun posting my paper in this forum.  I evaluate the potentials of possible solutions in one section, which I will likely post a few paragraphs at a time later this month, or perhaps next month.

There is always the horrible risk that we will clean up the environment and make the world a much better place, just to find out that climate change was an enormous hoax. 

Anyway, here is a great recent article about the Green New Deal. It is very good. It also does a good job of explaining my contempt for establishment Dems.

https://www.vox.com/energy-and-environme...sio-cortez

[Alan V]

There is always the horrible risk that we will clean up the environment and make the world a much better place, just to find out that climate change was an enormous hoax. 

Had we actually been smart about it, we would have made big changes before we detected climate change was happening at all.  The science was clear back in the 1980s, if not earlier.

As it is, we will likely have to live with whatever damage we are already doing for centuries to come.  The delayed effects are enormous.

(Your article looks interesting. I'll read it later.)

[Yonadav]

There is always the horrible risk that we will clean up the environment and make the world a much better place, just to find out that climate change was an enormous hoax. 

Had we actually been smart about it, we would have made big changes before we detected climate change was happening at all.  The science was clear back in the 1980s, if not earlier.

As it is, we will likely have to live with whatever damage we are already doing for centuries to come.  The delayed effects are enormous.

(Your article looks interesting.  I'll read it later.)

I don't know if I have given this link to you before. It is a rather lengthy article detailing the battle over global warming from '79 to '89. It's an impressive piece.

https://www.nytimes.com/interactive/2018...earth.html

[SYZ]

The actualities of climate change have always been subject to guesses.

In the 1970s, scientists were predicting the approach of a mini ice age, because of a lull in
20th century warming between the mid-1940s and mid-1970s.  Scientists Stephen Schneider
and Ichtiaque Rasool said "It is projected that man's potential to pollute will increase six- to
eight-fold in the next 50 years. If this increased rate of injection of particulate matter in the
atmosphere should raise the present global background opacity by a factor of 4, our calculations
suggest a decrease in global temperature by as much as 3.5°C. Such a large decrease in the
average surface temperature of Earth, sustained over a period of a few years, is believed to be
sufficient to trigger an ice age. However, by that time, nuclear power may have largely replaced
fossil fuels as a means of energy production."

And at that time, atmospheric scientist Reid Bryson "rejected anthropogenic warming even as
global temperatures climbed. In 1975 and 1976 papers, Bryson concluded that aerosol cooling
would dominate over CO2 warming—a fact he felt was demonstrated by recent temperatures.
As one of his papers put it, “Since 1940, the effect of the rapid rise of atmospheric turbidity
appears to have exceeded the effect of rising carbon dioxide, resulting in a rapid downward
trend of temperature. There is no indication that these trends will be reversed, and there is some
reason to believe that man-made pollution will have an increased effect in the future.”

Personally, I accept the science supporting global warming;  I've seen actual evidence of it in my local
physical environment in my lifetime.  Snow falling in my suburb of birth in Melbourne in 1949—never
to be seen since.  Garden hoses freezing regularly in Perth winters in the early 1970s—never to
be seen again.  The Murray River in South Australia effectively running dry at its mouth for the first
time in recorded history.  The water table in the Great Artesian Basin (the largest and deepest artesian
basin in the world), dropping to its lowest level in recorded history.

I certainly won't be around in (?) 2040, so I guess ultimately, the significance of global warming is a
moot point for me.  I do feel though for the kids being born today—what sort of world are they going
to be living in by the time they're my age?  Will the lack of water push them into a sort of "Mad Max"
scenario where people are killing each other for it?

[Alan V]

The actualities of climate change have always been subject to guesses.

In the 1970s, scientists were predicting [my bolding] the approach of a mini ice age, because of a lull in 20th century warming between the mid-1940s and mid-1970s.  Scientists Stephen Schneider and Ichtiaque Rasool said "It is projected [my bolding] that man's potential to pollute will increase six- to eight-fold in the next 50 years. If this increased rate of injection of particulate matter in the atmosphere should raise the present global background opacity by a factor of 4, our calculations suggest a decrease in global temperature by as much as 3.5°C. Such a large decrease in the average surface temperature of Earth, sustained over a period of a few years, is believed to be sufficient to trigger an ice age. However, by that time, nuclear power may have largely replaced fossil fuels as a means of energy production."

I see your point: there was still too much uncertainty early on.

However, people confuse scientific projections with predictions.  Projections are like thought experiments: "If present trends continue, where will we end up?"  Such projections have their uses, to get us to change the trends that may lead to later problems.

In fact, scientists aren't predicting anything about climate change, except as if-then statements with probabilities, because the biggest unknown variable is how we humans will act in the near future.  Will we change in big ways, continue with business-as-usual, or fall somewhere in between? Will we ramp up carbon capture and storage technologies to remove CO2 from the atmosphere?  That is why scientists work out a range of scenarios based on the best available information, and include the probabilities in their work.  They are trying to give us the tools to make the best possible decisions.

Further, even in the 1970s most scientists thought global warming would dominate any particulate-induced cooling. The scientists who speculated about global cooling were a minority.

Even further, both our available information and our computer models have improved so much since the 1970s, that there really can be no fair comparison between then and now.

[Alan V]

The Keeling Curve

In the mid-1950s, Charles Keeling at Caltech invented an instrument to measure CO2 in the atmosphere. He located his device at Mauna Loa Observatory in Hawaii, in an area free of local pollution. When Keeling started measuring CO2 in 1958, and in the first full year of measuring in 1959, it averaged 316 parts per million. In 2016, it measured 400 ppm all year round for the first time. That number is presently increasing at a rate of 2.5 ppm per year. This pattern has been confirmed by about 100 other sites located around the globe. This rate of increase is about 1000 times the rate during past natural warming periods.

The sawtooth pattern of the increase of CO2 in the atmosphere since 1958 is called the Keeling Curve. CO2 varies about 8 ppm on a seasonal cycle, due to deciduous trees taking up CO2 in the spring and releasing it in the fall in the northern hemisphere.

Since CO2 is only one of several greenhouse gases building up in the atmosphere, it is important to remember that although CO2 is now over 405 ppm, the CO2e is between 440 and 480 ppm, a level not seen on the earth for millions of years. In the 800,000 years before 1750, CO2 levels did not rise above 300 ppm. There is some controversy about what should be considered a safe level of CO2. Some say 450 ppm, while others say we passed the safe level at 350 ppm.

Land-based ecosystems take up about 25% of the CO2 emitted by fossil fuel use. Oceans absorb another 30%, leaving the remaining 45% to accumulate in the atmosphere.

The evidence that the CO2 buildup is caused by humans

The additional CO2 which has been accumulating in the atmosphere from deforestation and burning fossil fuels has an isotopic “fingerprint” which is depleted of CO2 13 and 14. This is the “smoking gun,” or how scientists know that most additional CO2 accumulating in the atmosphere over the last 250 years has come from human actions.

Fossil fuel burning can more than account for the rise in CO2. Scientists know how much coal, oil, and natural gas is burned each year. Emissions far overrun the earth’s natural ability to remove it from the atmosphere, so CO2 concentrations will remain elevated for centuries. No natural source has been identified, especially given the fast rate of accumulation.

Burning fossil fuels uses oxygen, and scientists have measured that oxygen has decreased by 0.1% in the atmosphere.

The observed warming in the lower atmosphere, or troposphere, and cooling in the upper atmosphere, or stratosphere, is exactly the pattern expected, since greenhouse gases trap heat close to the earth’s surface. Less heat is escaping to space. If the sun was responsible, a more uniform warming would be observed.

Since greenhouse gases reflect infrared whether the sun is shining or not, there has been more warming in the winter than the summer over the average, and more warming in the nighttime than the daytime over land.

The climate has departed from any known natural cycle, and is changing at an unnaturally fast rate. Climate models including greenhouse gas accumulations match scientific observations. This is yet more evidence that greenhouse gases are the cause of global warming.

[Alan V]

Other explanations?

There are only so many possible causes of climate change. The continental drift and massive volcanic eruptions of millions of years past are no longer possible explanations. Recent volcanic eruptions increase greenhouse gas emissions less than 1% of the total observed. Orbital variations work on much longer periods of time. Solar output has not increased significantly since 1979, when NASA began to monitor it using satellites. The usual small variations in solar output on an 11-year cycle is not a trend upwards. Only the greenhouse gases accumulating in the atmosphere can explain present climate change, and they are responsible for almost all of it. Other hypotheses, like the tenuous relationship between clouds and cosmic rays, must still explain why greenhouse gases do not produce the warming expected. Greenhouse gases alone are a sufficient explanation.

The consensus

The consensus of experts reviewing hundreds of studies of accumulating evidence is that there is a 95% chance that most of observed climate change over the past 60 years can be attributed to human activities and especially to the burning of fossil fuels. Without humans, there would be negligible warming or a slight cooling from other causes over the 20th century. This consensus includes such scientific institutions as the American Association for the Advancement of Science, the American Geophysical Union, the American Institute of Physics, the American Meteorological Society, NASA, the U.S. National Academy of Sciences, and the scientific academies of all major industrial nations. Multiple surveys have found that between 97 and 99% of qualified scientists support the consensus. Among the 3% or less who do not, most exhibited methodological flaws or other mistakes in their work, and there was no consensus between them about other possible causes. They have virtually no significant peer-reviewed science to back them up. So there is no consistent alternative theory to human-caused climate change.

[Alan V]

Anyway, here is a great recent article about the Green New Deal. It is very good. It also does a good job of explaining my contempt for establishment Dems.

https://www.vox.com/energy-and-environme...sio-cortez

Establishment Democrats have lots of other priorities than climate change, but I am certainly glad people are pressuring them to make climate change one of the highest priorities.

From your article: "The GND [Green New Deal] is, at its heart, a form of social-democratic populism. Its intent is to involve the entire citizenry in the shared project of adapting to the 21st century, and in so doing materially improve the quality of life of the poor and middle class. It is an attempt to rebalance the economy and the political system, away from a monomaniacal focus on private goods, toward a more generous view of public goods and public purpose."

Also: "The three core principles of the GND:
1) The plan must decarbonize the economy.
2) The plan must include a federal jobs guarantee and large-scale public investments.
3) The plan must include a just transition."

The third point is about "ensuring that all those jobs come with strong labor, environmental, and nondiscrimination standards."

I think all of this is great, but it is important to note that plenty of people in cities, states, and corporations are making progress on climate change even without any overarching federal policy. I personally am more for bottom up changes than top down changes, and think our political leaders will fall in line when they see the people below them actually leading on this issue.

[Yonadav]

Anyway, here is a great recent article about the Green New Deal. It is very good. It also does a good job of explaining my contempt for establishment Dems.

https://www.vox.com/energy-and-environme...sio-cortez

Establishment Democrats have lots of other priorities than climate change, but I am certainly glad people are pressuring them to make climate change one of the highest priorities.

From your article: "The GND [Green New Deal] is, at its heart, a form of social-democratic populism. Its intent is to involve the entire citizenry in the shared project of adapting to the 21st century, and in so doing materially improve the quality of life of the poor and middle class. It is an attempt to rebalance the economy and the political system, away from a monomaniacal focus on private goods, toward a more generous view of public goods and public purpose."

Also: "The three core principles of the GND:
1) The plan must decarbonize the economy.
2) The plan must include a federal jobs guarantee and large-scale public investments.
3) The plan must include a just transition."

The third point is about "ensuring that all those jobs come with strong labor, environmental, and nondiscrimination standards."

I think all of this is great, but it is important to note that plenty of people in cities, states, and corporations are making progress on climate change even without any overarching federal policy.  I personally am more for bottom up changes than top down changes, and think our political leaders will fall in line when they see the people below them actually leading on this issue.

Yeah, you and I have disagreed about this for years.  I have given up on the bottom up approach. People only want to make token changes to their lives, and even then the changes that they are most interested in are green signaling.  I swore off private motor vehicles because regardless of how fuel efficient they are, over half of any car's life time carbon footprint has been created before it has been driven a single mile. So I ride a bicycle. I ride a bicycle in the winter. I ride a bicycle in the rain. This has unquestionably cut down on my carbon footprint in a massive way. But I learned something else. I learned that the green signaling college professor who bought a Prius because he wants to be seen driving a 'green' car because he likes what it says about him has no respect for the more serious environmentalist who has sworn off cars completely. When the Prius owner despises the bicycle rider, there is no chance of meaningful bottom up environmentalism.

I have come to the conclusion that green signaling ultimately does more harm to the environmental cause than good. It sells environmentalism out by making it a consumer product.  When I see someone driving an EV, do I really see someone carrying water to a fire? No, not really. Why? Because over half of a car's lifetime carbon footprint has been created before it is driven for a single mile; the EV depreciates in value at twice the rate of a gasoline care; so there is a bit of a math problem there. Bottom up is bad at math, and green signalers don't really care about the math. They care about the image.

[Alan V]

There are 7.7 billion people in the world to try to take care of, as well as trying to save the future for people who, for the most part, are not even born yet. Present day people have their own needs and responsibilities, prior commitments, a lack of wherewithal, and other constraining factors, all of which must be taken into account too. A radical approach may be the straightest line between two points, but if there are too many obstacles in the way, it is realistically worthless. If you tried to force Americans to change, top down, they will reject you. You will get more Republican administrations. You may feel and even be superior in a certain way, but that won't change reality. However, if you teach people better and encourage them, they might surprise you. We are already making significant progress. Most of us just want to find a way to avoid sacrificing the progress we have actually achieved in our lives. That will take more time, sure, and time is running out. But it is, in my opinion, the only likely way to succeed.

[SYZ]

I swore off private motor vehicles because regardless of how fuel efficient they are, over half of any car's life time carbon footprint has been created before it has been driven a single mile...

Can you please provide a citation for this?  I don't accept your claim.

So I ride a bicycle. I ride a bicycle in the winter. I ride a bicycle in the rain. This has unquestionably cut down on my carbon footprint in a massive way...

This is an oversimplified "solution" unavailable to the majority of the population.  Obviously you live in an urban environment where you're not located 100km from the nearest commercial or retail centre.  It also reeks of self-satisfied smugness.

But I learned something else. I learned that the green signaling college professor who bought a Prius because he wants to be seen driving a 'green' car because he likes what it says about him has no respect for the more serious environmentalist who has sworn off cars completely. When the Prius owner despises the bicycle rider, there is no chance of meaningful bottom up environmentalism.

This is all rubbish.  You also use your concocted pejorative "green signalling".  No such thing—as you use the term.

Because over half of a car's lifetime carbon footprint has been created before it is driven for a single mile...

Are you losing the plot mate?  You've made this claim twice LOL.

...the EV depreciates in value at twice the rate of a gasoline car; so there is a bit of a math problem there.

Again, can you please provide a citation for this?  I don't accept your claim.

[Alan V]

Section 3: How we understand what is likely to occur in the future

The impacts

How much of an impact could a few degrees possibly have on the world? Won’t that make the world more pleasant? Isn’t CO2 good for the growth of plants? Won’t the growing season lengthen and crop yields become more productive? What will be the environmental impacts of climate change? Scientists assign probabilities to the spectrum of possible future scenarios, observe whether real world observations are consistent with their modeling of scenarios, and make helpful recommendations accordingly.

The benefits and the problems with the benefits

The growing seasons have already lengthened and will continue to do so. But that doesn’t help with other limiting factors of crop production, like water, pests, soil nutrients, and fertilizer. Further, crop production will also be harmed by more intense droughts, floods, and other extreme weather events, as well as by shifting weather patterns which make farming less predictable. The realities of climate change make it likely that while some areas benefit in the short run, others will be disrupted. Moderate additional warming will benefit food production in the U.S., Canada, and Europe while lowering production in other areas, especially in the tropical regions, which will be hurt even with modest warming.

So benefits in some areas will be offset by problems in others. CO2 and extra warmth will stimulate plant growth, humans will experience fewer cold-related illnesses, and the Arctic will become ice free at some point, allowing for new shipping routes and for discovering new mineral wealth. But problems will arise as well, including larger forest fires, the spread of destructive insects and other pests, widespread droughts, rising seas, and massive species loss, as I will discuss in more detail below.

Global warming also will likely delay the onset of the next ice age. However, as climate scientist James Hansen pointed out, “Forces instigating ice ages ... are so small and slow that a single chlorofluorocarbon factory would be more than sufficient to overcome any natural tendency toward an ice age.”