Learning Global Warming facts and fiction

[Webberweather53]

Webber, I appreciate your hard work, but you said something that I don't understand . You said that the release of man made fossil fuels have caused the warming. you also said barring a volcanic eruption we would continue to warm. Are you saying that a sudden burst of greenhouse gasses could cool the Atmosphere? Also, since there are daily small volcanic eruptions eruptions that release thousands of times more fossil fuels into the atmosphere than all the modern industrial and commercial activity does, why do you feel like the percent pf a percent is the devastating factor? The 1970's was the most polluted time of the modern world, yet 1976-77 was the coldest. The 1930's was by far less polluted by man, yet some of the hottest years in modern history are then. You seem like you are a little bit worried. Don't be. The climate is going to do what the climate is going to do. There are deserts where ancient wet lands used to be and vise versa. these happened long before we had weather records. We have reduced emissions dramatically since the 1970s, that should be helping, yet you say we continue to warm. It apparently is not going to stop this dangerous warming. So, if you are that worried, I suggest you put your trust in One who can comfort you, because we can't make it hotter or colder.

You do realize that Volcanoes release a lot more than CO2 right? Most major volcanic eruptions in modern history have led to cooling not warming of the climate due to the release of sulfate aerosols that get circulated into the stratosphere (El Chichon, Pinatubo, Krakatoa, Ilopongo (540 ish AD), etc.) and block incoming solar radiation.

The hottest years in modern history are all happening right now, we're much warmer than we were in the 1930s by any metric you look at.

 

[Downeastnc]

Webber, I appreciate your hard work, but you said something that I don't understand . You said that the release of man made fossil fuels have caused the warming. you also said barring a volcanic eruption we would continue to warm. Are you saying that a sudden burst of greenhouse gasses could cool the Atmosphere? Also, since there are daily small volcanic eruptions eruptions that release thousands of times more fossil fuels into the atmosphere than all the modern industrial and commercial activity does, why do you feel like the percent pf a percent is the devastating factor? The 1970's was the most polluted time of the modern world, yet 1976-77 was the coldest. The 1930's was by far less polluted by man, yet some of the hottest years in modern history are then. You seem like you are a little bit worried. Don't be. The climate is going to do what the climate is going to do. There are deserts where ancient wet lands used to be and vise versa. these happened long before we had weather records. We have reduced emissions dramatically since the 1970s, that should be helping, yet you say we continue to warm. It apparently is not going to stop this dangerous warming. So, if you are that worried, I suggest you put your trust in One who can comfort you, because we can't make it hotter or colder.

I imagine he means it would take a VEI 6-7 type event to put enough particulates in the upper atmosphere to create a net cooling effect....and that would halt the warming trend even if for just a few months/years....

Think Mt Pinatubo 1991 https://en.wikipedia.org/wiki/Mount_Pinatubo

The effects of the 1991 eruption were felt worldwide. It erupted roughly 10 billion tonnes (1.1×1010 short tons) or 10 km3 (2.4 cu mi) of magma, and 20 million tonnes (22 million short tons) of SO2, bringing vast quantities of minerals and toxic metals to the surface environment. It ejected more particulate into the stratosphere than any eruption since Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C (0.9 °F) in the years 1991–1993,[9] and ozone depletion temporarily saw a substantial increase.[10

 

[Downeastnc]

Its pretty obvious that man is having a impact, it is impossible that we are not. The earth has a CO2 sequestering cycle, when we came along and started pulling sequestered CO2 out of the ground and burning it releasing it into the atmosphere we upset that cycle....the earth has/had capacity to compensate to a degree but we are talking 20-40 gigatons of CO2 released every single year for the last what 20 yrs or so, to think that we are not having a impact is ridiculous.

The evidence is pretty cut and dry.....CO2 is up and so is global temps.....C02 has increased faster the last 20-50 years than at any other point in the known data sets, amazingly this increase matches up with humans using fossil fuels at a ever increasing rate...

I also agree that there are alarmist on the left trying to push agendas.....there is no doubt about it, worse though are the ones that totally dismiss it out of hand even in light of the evidence suggesting otherwise....heck Exxon did a internal study and came up with one of the most accurate temp profile predications showing the global warming caused by increase use of fossil fuels...

 

[WEATHERBOYROY]

You do realize that Volcanoes release a lot more than CO2 right? Most major volcanic eruptions in modern history have led to cooling not warming of the climate due to the release of sulfate aerosols that get circulated into the stratosphere (El Chichon, Pinatubo, Krakatoa, Ilopongo (540 ish AD), etc.) and block incoming solar radiation.

The hottest years in modern history are all happening right now, we're much warmer than we were in the 1930s by any metric you look at.

I suggest we try to release sulfate aerosols into the stratosphere then! It is a stupid road we're going down right now in this "save mother earth movement". Case and point; electric cars. We first of all manufacture a product that has to be moved that is 30 percent heavier. That means it takes 30 percent more horse power to move it. We think that trying to store energy in a container( that is a battery), that is not completely efficient, That green house emissions will be reduced?! Not to mention the inefficiencies of transport of the energy (electricity) which is produced at power plants that run on green house gas producing fuel, to the extremely heavy, and dangerous to the environment battery. Not to mention, the infrastructure which can't support more than a small percent of vehicles that run this way. Power lines, sub-stations, power polls, and houses would have to be reconfigured, which would in itself be a large greenhouse gas producing Industry. Then after a few years, when the battery dies, it would cost more than an engine to replace. Not to mention, no one except the extremely wealthy would buy an electric vehicle, if the government didn't subsidize the manufacturer to produce it and the retailer to sell it. It takes either an extremely gullible person, or at the very least a very superficial thinking person to follow this kind of thinking which comes from this movement.

 

[weatherfide]

You do realize that Volcanoes release a lot more than CO2 right? Most major volcanic eruptions in modern history have led to cooling not warming of the climate due to the release of sulfate aerosols that get circulated into the stratosphere (El Chichon, Pinatubo, Krakatoa, Ilopongo (540 ish AD), etc.) and block incoming solar radiation.

The hottest years in modern history are all happening right now, we're much warmer than we were in the 1930s by any metric you look at.

How do you know we are warmer than the 1930's? Where are the metrics? For accurate, uncontaminated measurements you need to be able to hold as many variables constant as you can. How can we do that and measure the earth's surface temperature from the 1930's? We didn't have nearly as much development in and around cities then, or even up until the 1950's. Also, what if one single source of CO2 and pollution is the culprit here? What if it's only air traffic, namely from jets, that is causing the problem? Banning air travel might be the only thing necessary. CO2 is heavier than air, right (44g/mol where air is 29g/mol)? Release in the boundary layer is going to see it pool up at the ground, where it is very likely to be taken up by plants and algae and unlikely to lead to any significant warming. Released in the upper atmosphere means, what exactly? Does it just collect up there, trapped by strong upper level winds? How much do we know about the distribution of CO2 in the atmosphere? Before widespread air travel, all CO2, except from volcanoes, was released at the surface. As you said in your post, other aerosols released from volcanoes overcome the CO2 warming and lead to cooling overall. What if we add the cooling aerosols to be released at the same time the exhaust from the jet engines is released, negating CO2's effects? Could it be this simple and avoid all of the social upheaval down on the surface?

 

[Webberweather53]

How do you know we are warmer than the 1930's? Where are the metrics? For accurate, uncontaminated measurements you need to be able to hold as many variables constant as you can. How can we do that and measure the earth's surface temperature from the 1930's? We didn't have nearly as much development in and around cities then, or even up until the 1950's. Also, what if one single source of CO2 and pollution is the culprit here? What if it's only air traffic, namely from jets, that is causing the problem? Banning air travel might be the only thing necessary. CO2 is heavier than air, right (44g/mol where air is 29g/mol)? Release in the boundary layer is going to see it pool up at the ground, where it is very likely to be taken up by plants and algae and unlikely to lead to any significant warming. Released in the upper atmosphere means, what exactly? Does it just collect up there, trapped by strong upper level winds? How much do we know about the distribution of CO2 in the atmosphere? Before widespread air travel, all CO2, except from volcanoes, was released at the surface. As you said in your post, other aerosols released from volcanoes overcome the CO2 warming and lead to cooling overall. What if we add the cooling aerosols to be released at the same time the exhaust from the jet engines is released, negating CO2's effects? Could it be this simple and avoid all of the social upheaval down on the surface?

The globe is much warmer than the 1930s and it's not even close. Cherry picking a small area of the CONUS that had one of the worst droughts in history (in large part which was man-made due to very poor farming practices) as evidence of global climate change not being real is nonsense.

 

[Webberweather53]

How do you know we are warmer than the 1930's? Where are the metrics? For accurate, uncontaminated measurements you need to be able to hold as many variables constant as you can. How can we do that and measure the earth's surface temperature from the 1930's? We didn't have nearly as much development in and around cities then, or even up until the 1950's. Also, what if one single source of CO2 and pollution is the culprit here? What if it's only air traffic, namely from jets, that is causing the problem? Banning air travel might be the only thing necessary. CO2 is heavier than air, right (44g/mol where air is 29g/mol)? Release in the boundary layer is going to see it pool up at the ground, where it is very likely to be taken up by plants and algae and unlikely to lead to any significant warming. Released in the upper atmosphere means, what exactly? Does it just collect up there, trapped by strong upper level winds? How much do we know about the distribution of CO2 in the atmosphere? Before widespread air travel, all CO2, except from volcanoes, was released at the surface. As you said in your post, other aerosols released from volcanoes overcome the CO2 warming and lead to cooling overall. What if we add the cooling aerosols to be released at the same time the exhaust from the jet engines is released, negating CO2's effects? Could it be this simple and avoid all of the social upheaval down on the surface?

The residence time of an average CO2 molecule in the atmosphere is on the order of several years-decades, whereas a lighter-than-average-air gas like water vapor is on the order of hours-several days because it precipitates in out very quickly (but is also replenished just as fast), so this argument about atomic weight really doesn't hold up. On the other hand, a large proportion say half of a half (~25%) of what we emit today will remain in the atmosphere several times longer than the average molecule, etc.

The half life of CO2 varies a lot depending on the source you look at but, the decay process is very exponential & non-linear because there are many physical mechanisms acting simultaneously at vastly different rates. CO2 absorption (at least initially via plants) occurs rapidly on land (months-years), the processes to absorb CO2 are very slow in the ocean, on the order of centuries (& made more slow by the fact that the ocean is warming, which decreases the solubility of dissolved CO2), & the act of carbon sequestration through interaction w/ calcium carbonate in the weathering of rocks is on the order of tens of thousands of years. Barring a huge unforeseen catastrophe &/or without major intervention from humans to sequester carbon back to where it came from (which we are fully capable of doing), we almost certainly won't see CO2 levels return to pre-industrial era levels for tens-hundreds of thousands of years.

I generally tend to agree with this statement here:
https://www.nature.com/articles/climate.2008.122
“About 50% of a CO2 increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years.”



Let's also just get something straight here, climate change isn't really about the actual temperatures themselves, & whether or not it was actually warmer or cooler at some distant time in Earth's past. Rather, the actual problem is rate of change we're imposing on the climate system thru the release of fossil fuels & the positive feedbacks that come with it to accentuate this change. Humans and other animal species on this planet are creatures of habit, and if the climate were to either warm or cool in a dramatic way, it forces all of us to either quickly adapt or perish, which is a very costly endeavor, particularly in the long run.

 

[WEATHERBOYROY]

I think there is a more plausible theory. It would make more since to believe that there has been overall continual warming with short periods of cooling over the last 4500 years. It would make since when you consider the "ice age" effects globally and how the ice has been receding ever since. Some great event happened at the beginning of that time that dramatically cooled the earth, and it has been recovering to it's original warmer state since then.

 

[weatherfide]

The residence time of an average CO2 molecule in the atmosphere is on the order of several years-decades, whereas a lighter-than-average-air gas like water vapor is on the order of hours-several days because it precipitates in out very quickly (but is also replenished just as fast), so this argument about atomic weight really doesn't hold up. On the other hand, a large proportion say half of a half (~25%) of what we emit today will remain in the atmosphere several times longer than the average molecule, etc.

The half life of CO2 varies a lot depending on the source you look at but, the decay process is very exponential & non-linear because there are many physical mechanisms acting simultaneously at vastly different rates. CO2 absorption (at least initially via plants) occurs rapidly on land (months-years), the processes to absorb CO2 are very slow in the ocean, on the order of centuries (& made more slow by the fact that the ocean is warming, which decreases the solubility of dissolved CO2), & the act of carbon sequestration through interaction w/ calcium carbonate in the weathering of rocks is on the order of tens of thousands of years. Barring a huge unforeseen catastrophe &/or without major intervention from humans to sequester carbon back to where it came from (which we are fully capable of doing), we almost certainly won't see CO2 levels return to pre-industrial era levels for tens-hundreds of thousands of years.

I generally tend to agree with this statement here:
https://www.nature.com/articles/climate.2008.122
“About 50% of a CO2 increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years.”



Let's also just get something straight here, climate change isn't really about the actual temperatures themselves, & whether or not it was actually warmer or cooler at some distant time in Earth's past. Rather, the actual problem is rate of change we're imposing on the climate system thru the release of fossil fuels & the positive feedbacks that come with it to accentuate this change. Humans and other animal species on this planet are creatures of habit, and if the climate were to either warm or cool in a dramatic way, it forces all of us to either quickly adapt or perish, which is a very costly endeavor, particularly in the long run.

What about the following:


"It is well known to scientists that the correlation between CO2 levels and RF to date is not, as many appear to assume, a linear correlation, in which each X increase in CO2 would produce the same Y increase in RF. Instead, the relationship is logarithmic.(8) That means each additional X increase of CO2 contributes a successively smaller amount of additional RF than the one before. The logarithmic curve can be calculated mathematically.(9) Mathematically, doubling total CO2, not merely the human-generated portion, from current levels (which is not now in prospect in either human or even geological terms) would theoretically increase CO2 contribution to RF by about 11.4 %; tripling, about 19.5%. In terms of degrees, the doubling implies a 1.7 degree Celsius increase, tripling about 2.0. Observed RF till now closely follows the theoretical curve (and also reflects downwelling of radiation from warming in the stratosphere and above and any other factors at work) (See citations 1-5 in the text above). Average of the annual increases in CO2 concentration in the period 2020-2021 is about 2.32 ppm;(10) a doubling at that rate would take about 184 years, a tripling about 368. Beyond that, the rate of increase continues to dwindle toward the infinitesimal."

This would suggest that the rate of change form CO2 induced RF would be low and would happen over hundreds of years. I think we can adapt to that.

 

[Webberweather53]

What about the following:


"It is well known to scientists that the correlation between CO2 levels and RF to date is not, as many appear to assume, a linear correlation, in which each X increase in CO2 would produce the same Y increase in RF. Instead, the relationship is logarithmic.(8) That means each additional X increase of CO2 contributes a successively smaller amount of additional RF than the one before. The logarithmic curve can be calculated mathematically.(9) Mathematically, doubling total CO2, not merely the human-generated portion, from current levels (which is not now in prospect in either human or even geological terms) would theoretically increase CO2 contribution to RF by about 11.4 %; tripling, about 19.5%. In terms of degrees, the doubling implies a 1.7 degree Celsius increase, tripling about 2.0. Observed RF till now closely follows the theoretical curve (and also reflects downwelling of radiation from warming in the stratosphere and above and any other factors at work) (See citations 1-5 in the text above). Average of the annual increases in CO2 concentration in the period 2020-2021 is about 2.32 ppm;(10) a doubling at that rate would take about 184 years, a tripling about 368. Beyond that, the rate of increase continues to dwindle toward the infinitesimal."

This would suggest that the rate of change form CO2 induced RF would be low and would happen over hundreds of years. I think we can adapt to that.

Ahh this looks like an excerpt taken from the WUWT denier website. The massive problem w/ this whole argument is the CO2 increase is also not linear & is in fact increasing exponentially due to increasing man-made emissions + positive feedbacks associated with them, offsetting any would be RF saturation from increased CO2. Sure, each doubling of CO2 increase has technically less of an effect than the previous doubling before that, but it's a moot point when the doubling rates are also increasing too. We need to change that asap.

 

[Rain Cold]

If man is the primary contributing factor to runaway global warming, and if runaway global warming is going to cause life on Earth to perish, then the only viable alternative is global population reduction. There simply isn't enough alternative energy today to transition away from fossil fuels, while maintaining living standards, food production, healthcare, infrastructure, growth, etc., supporting the global population as is. Has anybody been saying or doing anything along the lines of population reduction in the last several years?

 

[severestorm]

CO2 does have a positive forcing, but humans will not able to stop the rising temps for 50 years even if we become extinct today. By then the methane from Siberia will already push us past the tipping point. There's nothing humans can do bedsides geoengineering, which most are against because it's the cheapest and most cost effective method. It's all about $

 

[weatherfide]

Ahh this looks like an excerpt taken from the WUWT denier website. The massive problem w/ this whole argument is the CO2 increase is also not linear & is in fact increasing exponentially due to increasing man-made emissions + positive feedbacks associated with them, offsetting any would be RF saturation from increased CO2. Sure, each doubling of CO2 increase has technically less of an effect than the previous doubling before that, but it's a moot point when the doubling rates are also increasing too. We need to change that asap.

But the claim is that the narrow band of infrared energy that CO2 absorbs is already being captured nearly 100% by the existing CO2 in the atmosphere. It's like the accelerator pedal is pushed all the way down. How is adding more CO2 going to capture more infrared energy than is already being emitted? It takes time for the earth to heat up and increase the radiation in this narrow band where the abundant CO2 can absorb and radiate it back. You're going to have wildly different scenarios depending on your assumptions of how much the earth is radiating back (rate of warming) versus other factors that are trying to create an equilibrium. More heat means more water vapor, more clouds and precipitation and less solar energy reaching the surface.

I see your point about increasing the CO2 concentrations but I still don't know where this concentration is occurring. They are measuring
in Hawaii on a volcano at 10k ft. Where are the other measurements? What is the CO2 concentration distribution through the atmosphere? Is it equally dispersed? Is it higher over water or land? How much is it actually increasing? What is the rate of increase and what is the rate of increase of the infrared energy radiated from earth?

The climate system is a very complex system and I've seen how scientists have missed the mark on trying to predict the future. I don't trust that they have this sorted to the degree of certainty to justify taking control of huge swaths of the economy and sacrificing freedom in a technocracy.

 

[Rain Cold]

CO2 does have a positive forcing, but humans will not able to stop the rising temps for 50 years even if we become extinct today. By then the methane from Siberia will already push us past the tipping point. There's nothing humans can do bedsides geoengineering, which most are against because it's the cheapest and most cost effective method. It's all about $

Guarantee we're already engaging in geoengineering in some form or another. The economics aspect is pretty simple. There's no quick or easy or affordable way to transition away from FFs. If it's done by mandate, it will be arduous, disruptive, expensive, and it will force millions to become completely dependent on governments. Besides, if we believe what we're being told and have been told for years, we've passed the point of no return many times now.

 

[weatherfide]

If man is the primary contributing factor to runaway global warming, and if runaway global warming is going to cause life on Earth to perish, then the only viable alternative is global population reduction. There simply isn't enough alternative energy today to transition away from fossil fuels, while maintaining living standards, food production, healthcare, infrastructure, growth, etc., supporting the global population as is. Has anybody been saying or doing anything along the lines of population reduction in the last several years?

I know someone that is all about that. He's been very active in Africa. He likes vaccines a lot, too.

 

[Rain Cold]

But the claim is that the narrow band of infrared energy that CO2 absorbs is already being captured nearly 100% by the existing CO2 in the atmosphere. It's like the accelerator pedal is pushed all the way down. How is adding more CO2 going to capture more infrared energy than is already being emitted? It takes time for the earth to heat up and increase the radiation in this narrow band where the abundant CO2 can absorb and radiate it back. You're going to have wildly different scenarios depending on your assumptions of how much the earth is radiating back (rate of warming) versus other factors that are trying to create an equilibrium. More heat means more water vapor, more clouds and precipitation and less solar energy reaching the surface.

I see your point about increasing the CO2 concentrations but I still don't know where this concentration is occurring. They are measuring
in Hawaii on a volcano at 10k ft. Where are the other measurements? What is the CO2 concentration distribution through the atmosphere? Is it equally dispersed? Is it higher over water or land? How much is it actually increasing? What is the rate of increase and what is the rate of increase of the infrared energy radiated from earth?

The climate system is a very complex system and I've seen how scientists have missed the mark on trying to predict the future. I don't trust that they have this sorted to the degree of certainty to justify taking control of huge swaths of the economy and sacrificing freedom in a technocracy.

Much of this whole debate is hypothesis. There is hard data, sure, but we do not know what it portends. And we're not even close to understanding what mechanisms the Earth has to combat increased CO2. It is as much of an emotional issue as it is a scientific one, and you can clearly observe that anytime a discussion about it pops up. Like I said yesterday, we are so certain of everything.

 

[severestorm]

Guarantee we're already engaging in geoengineering in some form or another. The economics aspect is pretty simple. There's no quick or easy or affordable way to transition away from FFs. If it's done by mandate, it will be arduous, disruptive, expensive, and it will force millions to become completely dependent on governments. Besides, if we believe what we're being told and have been told for years, we've passed the point of no return many times now.

Understand that completely. Biden's already planning to engage in SO2 injection into the stratosphere, similar to volcano eruption. It looks like it will be 10 billion a year to being the temp down 1 degree Celsius. About 10% of EPA's annual budget for example. It's far cheaper than carbon sequestration for example which costs $600 per ton of CO2.

White House is pushing ahead research to cool Earth by reflecting back sunlight

There are several kinds of sunlight-reflection technology, and none have been thoroughly researched due to a perceived moral hazard. But sentiment is shifting.

www.cnbc.com

 

[Rain Cold]

Understand that completely. Biden's already planning to engage in SO2 injection into the stratosphere, similar to volcano eruption. It looks like it will be 10 billion a year to being the temp down 1 degree Celsius. About 10% of EPA's annual budget for example. It's far cheaper than carbon sequestration for example which costs $600 per ton of CO2.

White House is pushing ahead research to cool Earth by reflecting back sunlight

There are several kinds of sunlight-reflection technology, and none have been thoroughly researched due to a perceived moral hazard. But sentiment is shifting.

www.cnbc.com

Because messing with things we don't understand always works out well.

 

[severestorm]

Because messing with things we don't understand always works out well.

Better than the Amazon completely burning down which it will if this doesn't happen.

 

[Iceagewhereartthou]

What is there to debate exactly? Because it certainly isn't the fact that the globe is warming today mainly because of man-made fossil fuels being released into the atmosphere and feeding back onto the earth system to accelerate their release from other additional natural and man-made sources sources to warm the earth even faster (positive feedbacks), at a rate that makes even the PETM look like a drop in the bucket.

The fact is that the scientific community and policy makers have long moved past this long, tired, baseless arguments like these decades ago & this so-called "debate" on whether or not we're the primary cause of today's warming, as you're trying to spin it, is a figment of people's imagination who have never spent a single day in their lives actually trying to understand how the climate system works, but instead regurgitate their favorite sound bites from their side of the political aisle, suddenly think because of this, they are suddenly experts on the topic, & refuse to accept any contradictory factual evidence to change their beliefs on the issue.

"Facts" can be hard to present in a way that removes bias and conjecture. Is it a fact that much of the US is warmer than it was 50 years ago? Many would say yes. I know my area seems warmer and gets less snow, but do I have enough data to say that the whole country has factually warmed (or the whole planet), and it is absolutely due to man induced activities? I doubt it. The same scientists tell us there is more ice volume in the antarctic than at any time in the satellite era. The same scientists told us the Arctic would be ice free by the year 2000, or 2010, or 2020, or.... . Which are facts and which are biased conjecture? We know that most of our long-term temp reading stations have been influenced by the growth of cities and their heat island effects. We could say these areas are factually warmer b/c we have the data, but we also have to recognize that particular data describes micro climates and it would be inappropriate to apply on a global scale.

The evidence points to the Earth having been much cooler and much warmer in past eras and there is little reason to doubt this. They could have been due, at least in part, to CO2 (ie volcanic eruptions) but they could have also been due to many other reasons we do not yet know enough about; such as earth, water, or solar patterns we don't have enough data on. One thing is for certain, those changes weren't due to human activity. You speak about the rate of change and that is a valid point. However, we can only guess at past rates of change, as well as their causes. The current rate of change may not be dissimilar from past rates of change. So which is fact and which is conjecture? Just because we see a fast current rate of change does not mean we know exactly why. Maybe human activity is at least partially responsible, but because we know it wasn't at all in the past, I think it is scientifically irresponsible and manipulative to say it "absolutely and factually" is the reason now; and a discussion cannot even be had.

It's also intersting you mention politics and I think it's too bad politics have been so closely intertwined with this. Bias and error get worked into it from both sides of the aisle. But the political interference is one of the many reasons why I take pause before jumping on board with what we are being told. The "you have to believe this or you are a denier" crowd is almost exclusively on the left, and these are the same people who think that men can "factually" have babies and that 2+2=4 is a racial distortion of mathematics. I am not jumping on board with any facts that come from the same source as that, without serious thought and distrust.