Question about climate change

[Hercules56]

Good evening.

I have a question about global warming that I was hoping folks could help me with.

I see from the Vostok ice core data graph 2, posted in a link below, that over the last 18,000 years CO2 ppm has gradually increased from about 180 ppm to a little less than 300 ppm.

However during this period of gradual CO2 ppm increase, we see average temperatures often increase dramatically (+2.5C) then decrease dramatically, even though there is no sudden change in CO2 ppm (according to the graph).

My question is: do the Vostok ice cores also show periods of rapid and sudden CO2 ppm increase with no corresponding increase in temperature?

http://www.daviesand.com/Choices/Precautionary_Planning/Closer_Look/index.html

Thanks for your help.

 

[macdoc]

You are perhaps confusing CO2 as feedback versus a forcing.

CO2 as a Feedback and Forcing in the Climate System

https://www.yaleclimateconnections....a-feedback-and-forcing-in-the-climate-system/

The oceans are warming as we exit the Great Ice age and that releases more C02 in a feedback loop.
Along come us and we introduce fossil carbon and a new forcing but I assume you understand that

The exit from an ice age is jagged

This reads current to the left.

as the climate oscillates for a variety of reasons including forest cover, ocean current changes, volcanism, even continental drift on a long scale plus variations in the Milankovitch cycles versus the tilt of the planet.
http://www.indiana.edu/~geol105/images/gaia_chapter_4/milankovitch.htm

The rapid shifts ( in geological terms ) are not CO2 driven - for instance an bollide strike MIGHT have caused the sudden change to the climate some 14,000 years ago where the Ice Age exit was suddenly reversed....( Younger Dryas )
https://www.ncdc.noaa.gov/abrupt-climate-change/The Younger Dryas

Crazy amount of controversy around the event ...good read.

Hope that helps.

 

[Hercules56]

You are perhaps confusing CO2 as feedback versus a forcing.



https://www.yaleclimateconnections....a-feedback-and-forcing-in-the-climate-system/

The oceans are warming as we exit the Great Ice age and that releases more C02 in a feedback loop.
Along come us and we introduce fossil carbon and a new forcing but I assume you understand that

The exit from an ice age is jagged

This reads current to the left.

[qimg]https://serc.carleton.edu/download/images/15045/vostok_ice_core_data.png[/qimg]

as the climate oscillates for a variety of reasons including forest cover, ocean current changes, volcanism, even continental drift on a long scale plus variations in the Milankovitch cycles versus the tilt of the planet.
http://www.indiana.edu/~geol105/images/gaia_chapter_4/milankovitch.htm

The rapid shifts ( in geological terms ) are not CO2 driven - for instance an bollide strike MIGHT have caused the sudden change to the climate some 14,000 years ago where the Ice Age exit was suddenly reversed....( Younger Dryas )
https://www.ncdc.noaa.gov/abrupt-climate-change/The Younger Dryas

Crazy amount of controversy around the event ...good read.

Hope that helps.

First of all, you REALLY know your stuff and I appreciate that.

Though I think you're a bit above my head.

I see and understand that rapid climate shifts are not CO2 driven, as far as the Vostok ice core data is concerned. This is due to CO2 concentrations changing very gradually, from what I gather.

The prevailing logic is that the sudden and dramatic increase in CO2 ppm will lead to an equally sudden and dramatic increase in avg Earth temperatures and related climate changes.

My real question is: if we have never seen such a quick and dramatic CO2 concentration increase before in the geologic record, how do we know how temperature and climate will react? Is it all just an assumption or do we have actual historical data that could corroborate such a climate model?

Yes, I know that the Vostok ice core data shows a clear corollation between CO2 ppm and temp. changes, but as I pointed out in my OP there is data from the same ice cores that show rapid temperature changes without any corresponding CO2 changes, and that makes me wonder if the opposite scenario may be possible.

Cheers.

 

[Red Baron Farms]

First of all, you REALLY know your stuff and I appreciate that.

Though I think you're a bit above my head.

I see and understand that rapid climate shifts are not CO2 driven, as far as the Vostok ice core data is concerned. This is due to CO2 concentrations changing very gradually, from what I gather.

The prevailing logic is that the sudden and dramatic increase in CO2 ppm will lead to an equally sudden and dramatic increase in avg Earth temperatures and related climate changes.

My real question is: if we have never seen such a quick and dramatic CO2 concentration increase before in the geologic record, how do we know how temperature and climate will react? Is it all just an assumption or do we have actual historical data that could corroborate such a climate model?

Yes, I know that the Vostok ice core data shows a clear corollation between CO2 ppm and temp. changes, but as I pointed out in my OP there is data from the same ice cores that show rapid temperature changes without any corresponding CO2 changes, and that makes me wonder if the opposite scenario may be possible.

Cheers.

Actually Mac explained it exactly correct, but you are still stuck.

CO2 can be both a feedback and a forcing. When it is a feedback, the temperature change is caused by something else, and the CO2 changes follow, modifying the result.

But deep in the geological past, we humans were not burning fossil fuels or plowing up the grasslands or chopping down the forests. So the CO2 as the primary forcing event is pretty rare. Usually it was a reinforcing feedback for some other forcing like the Milankovitch Cycle.

This time it is different though. We will still see the feedback of course, but we also are burning huge quantities of fossil fuels. So the initial spike in temps is not from milankovitch cycles, but instead is human caused.

This is why the proper term is Anthropogenic Global Warming (AGW), and not just ordinary natural global warming. Once the natural feedback CO2 hits we are in big troubles if we haven't already started pretty substantial worldwide efforts to mitigate what's coming.

Luckily it's like a slow motion train wreck. We still have time to get off the tracks. But the longer we delay the worse it will be. It's the old paradigm "A stitch in time saves nine".

 

[Hercules56]

Actually Mac explained it exactly correct, but you are still stuck.

CO2 can be both a feedback and a forcing. When it is a feedback, the temperature change is caused by something else, and the CO2 changes follow, modifying the result.

But deep in the geological past, we humans were not burning fossil fuels or plowing up the grasslands or chopping down the forests. So the CO2 as the primary forcing event is pretty rare. Usually it was a reinforcing feedback for some other forcing like the Milankovitch Cycle.

So I must ask, if in most of the geologic record CO2 was not a cause of global warming but its increase was simply a reaction to other environmental factors, how do we know for sure that our rapid increase in CO2 ppm can in fact become a forcing element to world temps? How can we know if we have no actual evidence of it ever happening before? How can we know for sure, if the geologic record has examples of world temps increasing and decreasing rapidly without any significant change in CO2 levels?

Another thing that concerns me is that the Vostok graphs that we are all very familiar with, and Al Gore famously displaced in "An Inconvenient Truth", covers CO2 and temperatures over 400,000 years. Those graphs showed a pretty good corrolation between CO2 and temperatures...over 400,000 years.

But if we look at Vostok data over the last 18,000 years, the corrollation isn't as perfect. It generally follows, but there are several examples where it does not. There are several examples where temps went up 2 degrees celsius or MORE, without any significant change in CO2. Temps also went down 2 degrees, again with no changes in CO2.

and all the IPCC predictions are not for the next 10,000 years...or 1,000 years...but merely 100 years.

If the corrolation between CO2 ppm and temperature changes becomes less and less clear and exact the shorter the time period we observe, and we have in the geologic record lots of examples of world temps going UP or DOWN 2+ degrees without any significant change in CO2, how the hell can we possible predict what will happen by 2100 if we increase CO2 ppm to say 500 or 600 ppm?

I know I sound like a climate change denier, but Im not. Im just trying to fully understand the logic and science behind IPCC predictions and analysis, considering the little bits of data that are available to the public, such as only three examples of Vostok ice core graphs

 

[macdoc]

So I must ask, if in most of the geologic record CO2 was not a cause of global warming but its increase was simply a reaction to other environmental factors, how do we know for sure that our rapid increase in CO2 ppm can in fact become a forcing element to world temps? How can we know if we have no actual evidence of it ever happening before? How can we know for sure, if the geologic record has examples of world temps increasing and decreasing rapidly without any significant change in CO2 levels?

You are far off track here ...C02 IS a forcing element ....if you can't get that far you don't belong here. It's a table top experiment for science fairs.

It's in the oceans and when released by a warming climate or absorbed by a cooling climate due to the Milankovich cycles - the feedback aspect is the ocean absorption release cause by another external forcing ( Milankovich and the sun/tilt )

As far as it happening before ...it certainly has ..try looking up Siberian traps.

https://www.youtube.com/watch?v=PNs9U4qVOII

and

https://www.livescience.com/41909-new-clues-permian-mass-extinction.html

This is the very long term concern as we are actually releasing more CO2 per year than the SIberian traps ....but that increase occurred over a very long period. We are doing it in hundreds of years if not 10s.

As far as how do we know ?? Climatologists have more and more sophisticated models that closely follow the impact of rising C02. The hard thing to predict is what we will do in terms of controlling, reducing or even removing CO2.

James Hansen made an incredible prediction - he modelled three scenarios in 1988...the black line is the actual temperature observed.

BTW Skeptical Science is a very good resource to answer questions
https://www.skepticalscience.com/Hansen-1988-prediction.htm

as is

http://www.realclimate.org/index.php/archives/2007/05/start-here/

run by climate scientists ...not retired weathermen

Even Forbes gets it correct when they hire the correct writers
https://www.forbes.com/sites/starts...global-warming-almost-perfectly/#4d5d01ea6614

The more difficult known unknown is how sensitive the climate is to CO2 ...the down side is that every time we hone on on a more accurate assessment of that it comes on the high side of outcomes ie more sensitive.

So yeah there are still details ....but bottom line it's getting warmer, we're responsible and have only a decade left to limit the damage.

Me? ....don't think we will short of a Manhattan Project level response by the whole world or a very early and significant tech break through in actively removing CO2 from the atmosphere.

There is also geo-engineering but that is fraught as well.

https://en.wikipedia.org/wiki/Climate_engineering

welcome to the Anthropocene.

 

[Red Baron Farms]

So I must ask, if in most of the geologic record CO2 was not a cause of global warming but its increase was simply a reaction to other environmental factors, how do we know for sure that our rapid increase in CO2 ppm can in fact become a forcing element to world temps? How can we know if we have no actual evidence of it ever happening before? How can we know for sure, if the geologic record has examples of world temps increasing and decreasing rapidly without any significant change in CO2 levels?

Another thing that concerns me is that the Vostok graphs that we are all very familiar with, and Al Gore famously displaced in "An Inconvenient Truth", covers CO2 and temperatures over 400,000 years. Those graphs showed a pretty good corrolation between CO2 and temperatures...over 400,000 years.

But if we look at Vostok data over the last 18,000 years, the corrollation isn't as perfect. It generally follows, but there are several examples where it does not. There are several examples where temps went up 2 degrees celsius or MORE, without any significant change in CO2. Temps also went down 2 degrees, again with no changes in CO2.

and all the IPCC predictions are not for the next 10,000 years...or 1,000 years...but merely 100 years.

If the corrolation between CO2 ppm and temperature changes becomes less and less clear and exact the shorter the time period we observe, and we have in the geologic record lots of examples of world temps going UP or DOWN 2+ degrees without any significant change in CO2, how the hell can we possible predict what will happen by 2100 if we increase CO2 ppm to say 500 or 600 ppm?

I know I sound like a climate change denier, but Im not. Im just trying to fully understand the logic and science behind IPCC predictions and analysis, considering the little bits of data that are available to the public, such as only three examples of Vostok ice core graphs

How does rare become never? How does less than expected become none? You are certainly taking little things and making them seem far more important than they really are.

To begin with there are many factors not just one or two. CO2 could be high but the solar cycle low and volcanic activity and albedo high to more than offset those.
So you can't just look at a single factor and know everything in the system. You need to include all the factors. You also need to understand that the earth takes time to heat or cool simply due to its huge size. So temps can be cool, while the radiative imbalance is still increased. Just watch a pot boil, the cliche' but highlights the delayed effect, and multiply that by a gazillion!

Maybe it would have gone down 4 degrees, but the high CO2 meant it only went down 2 degrees. Or maybe it would have dropped a degree, but the high CO2 made it rise 2 degrees instead? See what I mean? You can't just look at single factors and expect to understand. It's like jumping up in a falling elevator, are you really going upwards? Or just slightly less downwards? Until you include all the factors, you really can't know.

However there are those that have studied the empirical evidence with a skeptical eye.

 

[Pixel42]

We know that increasing the CO2 in the atmosphere will increase average surface temperature because CO2 is a greenhouse gas.

The climate system is extremely complicated, at any one time there will be several forcings and feedbacks in play. Some will be in the same direction and will reinforce each other, and others will be in opposite directions and will tend to cancel each other out. You can't expect to look at one single component of the climate system, like the amount of CO2 in the atmosphere, and see it rising and falling in sync with global temperatures.

 

[lomiller]

Good evening.

I have a question about global warming that I was hoping folks could help me with.

I see from the Vostok ice core data graph 2, posted in a link below, that over the last 18,000 years CO2 ppm has gradually increased from about 180 ppm to a little less than 300 ppm.

However during this period of gradual CO2 ppm increase, we see average temperatures often increase dramatically (+2.5C) then decrease dramatically, even though there is no sudden change in CO2 ppm (according to the graph).

My question is: do the Vostok ice cores also show periods of rapid and sudden CO2 ppm increase with no corresponding increase in temperature?

http://www.daviesand.com/Choices/Precautionary_Planning/Closer_Look/index.html

Thanks for your help.

Most of the "Temperature changes" you are seeing are noise in the proxy data or reflect changes in local conditions. There is enormous thermal inertia in the system so global temperatures do not actually change that fast. You can think of most of those rapid ups/downs as being a reflection on uncertainty in that particular proxy rather than actual changes.

The best approach to temperature reconstruction is to combine as many different proxy's as possible. The more data you have the less uncertainty there is and the smoother the whole thing looks. You never remove all the uncertainty though, and uncertainty is typically greater the farther back in time you look because there are fewer proxies to look at.

 

[lomiller]

This link has some temperature reconstructions that more accurately show what global temperatures were doing over the last 15000 years.
https://skepticalscience.com/the-two-epochs-of-marcott.html

This spike in temperatures since 1900 may represent the fastest global warming in the last 65 million years while ocean acidification may be the fastest in 300million years.

 

[Hercules56]

You are far off track here ...C02 IS a forcing element ....if you can't get that far you don't belong here. It's a table top experiment for science fairs.

It's in the oceans and when released by a warming climate or absorbed by a cooling climate due to the Milankovich cycles - the feedback aspect is the ocean absorption release cause by another external forcing ( Milankovich and the sun/tilt )

As far as it happening before ...it certainly has ..try looking up Siberian traps.

https://www.youtube.com/watch?v=PNs9U4qVOII

and

https://www.livescience.com/41909-new-clues-permian-mass-extinction.html

This is the very long term concern as we are actually releasing more CO2 per year than the SIberian traps ....but that increase occurred over a very long period. We are doing it in hundreds of years if not 10s.

As far as how do we know ?? Climatologists have more and more sophisticated models that closely follow the impact of rising C02. The hard thing to predict is what we will do in terms of controlling, reducing or even removing CO2.

James Hansen made an incredible prediction - he modelled three scenarios in 1988...the black line is the actual temperature observed.

[qimg]https://www.skepticalscience.com//pics/Hansen1988vsGISSthru2016.jpg[/qimg]
.

This is fascinating.

Ok, it looks like we may be right that increased CO2 ppm will raise the Earth's average yearly temps. I guess I am finally convinced.

Now, here's my next question: How can we claim to predict with any sort of certainty what the climatic results of this will be?

As a college student I watched "Before the Warming", which I believe is one of the first tv series about Climate Change. Many of its predictions have not yet come true. "An Inconvenient Truth" predicted Ground Zero would be under water. Again, never happened.

I understand that the Earth's climate is a giant and complex mixture of many sub-climates, affected by all sorts of things like sunspots, the Earth's erratically wobbly rotation, tilt relative to the sun. El Nino, La Nina, random volcanic eruptions, the Gulf Stream and connected warm/cold water currents, and lots of other stuff.

I worry that some folks err on the side of extremism when it comes to predicting the effects of Climate Change. Why? Maybe cause its human nature to expect the worst.

If I had to make a bet what the Earth will look like in 30 years, when I turn 72? I predict that the scientists were right about the warming, but did not anticipate all sorts of other environmental factors and events that ended up making reality not even half as bad as their dire predictions. We've seen this happen many times before, and my gut says it will happen again.

Not because folks at the IPCC are dishonest or sadistically wish to scare people into action, but because humans often presume too much and can't foresee everything that the Earth is gonna throw at us.

Do I think we should reduce carbon emissions? Yes. Do I think we should do it in such a rapid and costly way as the Green Deal proposes? No.

 

[macdoc]

You are fooling yourself ....in a very bad way ....plain old wishful thinking since you now have the information to accept the science.

You saw Hanson's projections from 1988 and he was slightly conservative yet you won't accept the projection and warning of a world group of scientists with far more sophisticated tools than Jim had.
The IPCC reports tends to get watered down by political interests.

Take your thinking and consider the obverse - what happens it's worse ?

I live on The Great Barrier Reef ......it's dying.

Apr 19, 2018, 12:24pm
Half Of The Great Barrier Reef Has Died Since 2016

Aerial view of heart-shaped Heart Reef, part of the Great Barrier Reef of the Whitsundays in the Coral sea, Queensland, Australia. (Photo by: Arterra/UIG via Getty Images)
The world's largest coral reef system, visible even from outer space, has lost half of its coral in the past two years. The Great Barrier Reef, once a colorful and visible display of biodiversity and a symbiotic ecosystem, now resembles a ghost town where life once flourished.

https://www.forbes.com/sites/trevor...-reef-coral-has-died-since-2016/#1b143f6b5f9f

and Forbes is not known for hysteria.

And

Miami Will Be Underwater Soon. Its Drinking Water Could Go First

https://www.bloomberg.com/news/features/2018-08-29/miami-s-other-water-problem

Rising seas: 'Florida is about to be wiped off the map' | Environment ...
https://www.theguardian.com/.../2018/.../rising-seas-florida-climate-change-elizabeth-rus...
Jun 26, 2018 - Sea level rise: Miami and Atlantic City fight to stay above water ... empty teal swivel chairs – will all be underwater in the not-so-distant future.

30 US cities that could be underwater by 2060 - Business Insider
https://www.businessinsider.com/30-us-cities-that-could-be-underwater-soon-2018-10
Oct 3, 2018 - Livable land that will be underwater by 2060: 25.7% ..... In Miami, king tides are the highest tides of the year and coincide with full moons during

Sea Level Rise Will Flood Hundreds of Cities in the Near Future
https://news.nationalgeographic.com/.../sea-level-rise-flood-global-warming-science/
Jul 12, 2017 - It will affect as many as 670 coastal communities, including Cambridge, Massachusetts; Oakland, California; Miami and St. Petersburg, Florida; ...

 

[Pixel42]

Now, here's my next question: How can we claim to predict with any sort of certainty what the climatic results of this will be?

The climate forcing produced by doubling the amount of CO2 in the atmosphere is actually quite simple to calculate, it will increase average surface temperature by just over one degree Celsius. What's much harder to calculate is the total effect once positive feedbacks are taken into account. Estimates have ranged from less than 2 degrees to over 5 and a great deal of work has been going on to try to narrow that down, both by looking at past natural climate change and by creating sophisticated computer models. The good news is that most of that work is pointing to a value nearer the lower end of that range than the upper, with a value of around 2.5 to 3 degrees looking most likely.

So far we've increased the amount of CO2 in the atmosphere by about 40%, and average surface temperature has increased by about one degree. At the current rate of emissions we will have doubled it by the end of this century. If we continue to burn fossil fuel until it's all gone we will double it at least once more.

In addition there are knock on effects, such as the thawing of frozen tundra releasing methane (also a greenhouse gas) into the atmosphere.

So although certainty is indeed hard to come by, I think we have a reasonable handle on the scale of the problem we are creating. The IPCC's reports are the best source of information if you want more detail:

https://www.ipcc.ch

It's true that there might be currently unknown factors that could mitigate the effect, but there are just as likely to be currently unknown factors which exacerbate it. What we do know is that past major extinction events always appear to have been associated with rapid climate change.

 

[lomiller]

This is fascinating.

Ok, it looks like we may be right that increased CO2 ppm will raise the Earth's average yearly temps. I guess I am finally convinced.

"finally convinced"? It's an application of the first law of thermodynamics, why would you need extra convincing?

Now, here's my next question: How can we claim to predict with any sort of certainty what the climatic results of this will be?

That depends on the prediction. With global temperature change for a given CO2 scenario the "predictions" are simply the result of applying the physics and calculating the result. Many different people have replicated the physics and they all arrive at similar results. Furthermore these results agree with the paleo-climate data for similar scenarios. There is A LOT of scientific evidence supporting them.

"An Inconvenient Truth" predicted Ground Zero would be under water. Again, never happened.

Did you really watch An Inconvenient Truth or are you just relying on Strawmen that have been published you about it.

An Inconvenient Truth suggests that we could see as much as 20 feet of sea level rise which would put Ground Zero below sea level (not necessarily under water). This is a prediction well supported by the scientific evidence. The best case for reduced CO2 emissions puts as at temperature and atmospheric CO2 levels above the Eemian maximum when sea levels were 20-30 feet higher than today.

What An Inconvenient Truth does no do is predict when this will happen. It certainly never said we should have reached these levels by now. Most estimates say it could take up to 500 years. However, current warming is so far off the scale wrt to how fast it's occurring so it could be much more rapid than that.

I understand that the Earth's climate is a giant and complex mixture of many sub-climates, affected by all sorts of things like sunspots, the Earth's erratically wobbly rotation, tilt relative to the sun. El Nino, La Nina, random volcanic eruptions, the Gulf Stream and connected warm/cold water currents, and lots of other stuff.

Global temperature trends are driven by global energy Ballance. Energy out vs energy in. The "complex mixture" you refer to is a function of how the new energy gets distributed in the oceans/atmosphere. Uncertainty in the latter doesn't change the former so regardless of what we scientists uncover, it's highly unlikely to change the global temperature trend that is causing all the havoc.

 

[macdoc]

This is the energy exchange between incoming solar radiation and outgoing infrared radiation.

Greenhouse gases absorb the outgoing IR selectively so the heat slowly accumulates until we reach a new radiative balance.

Unfortunately CO2 is cumulative in the atmosphere for human terms so the more we add the radiative balance continues to be off and the atmosphere gets warmer ( and the oceans importantly ).

Some gases like methane ( cow farts amongst other sources ) are 20x more absorptive but don't stay in the atmosphere as long as CO2...but it speeds the heating when we continue to add to the gases.

There is millions of tons of greenhouse gases ..methane and CO2 locked up in the tundra and continental shelves all over the planet.

Warming starts to release thos gases ....IS releasing those gases.

https://climate.nasa.gov/news/2785/...t-of-methane-possible-from-arctic-permafrost/

That is a feedback we cannot stop and we cannot predict but we do KNOW and can observe it happening ....so when I said ...what if it's worse than projections ....that's one of the known unknowns....we know it's occuring, we know it's adding greenhouse gases on a very large scale...we do not know the limits of that.....it's a wicked positive feedback and we may have passed the tipping point ......we just don't know but we dare not take the risk.

and just in

New research from Arctic: Thawing permafrost peatlands may add to atmospheric CO2 burden
Date:
March 1, 2019
Source:
University of Eastern Finland
Summary:
A new study finds that peatlands may strengthen the permafrost-carbon feedback by adding to the atmospheric CO2 burden post-thaw.

https://www.sciencedaily.com/releases/2019/03/190301101825.htm

 

[macdoc]

And climate change is not a "future thing" as it was when I first read about its distant threat in the 50s and even in the 80s....when it seemed a far off risk..

It's now ...and costing a lot already ...

Sea-level rise has cost homeowners on the East and Gulf coasts nearly $16 billion in property value as floods and the threat of flooding drive some buyers away, according to a study released this week.
Analysts at the nonprofit First Street Foundation in Brooklyn studied millions of residential home sales in 17 states from Maine to Alabama and found that coastal property values were rising at a slower rate in flood-prone areas than in areas that did not flood.
“The market is already reacting,” First Street Executive Director Matthew Eby said. “There’s no longer a conversation of what sea-level rise will do in 2050 or 2100.”

more
https://www.scientificamerican.com/...ked-home-owners-for-16-billion-over-12-years/

 

[novaphile]

It's funny how these things affect people in such different ways.

I first heard about "the greenhouse effect" in the mid 70's.

It caused me to join "Friends of the Earth" and later "The Alternative Technology Association".

I build my first solar hot water heater, out of rubbish-dump scraps, before I turned 20.

At no time did I say: "I must buy a car, fit a 12 cylinder diesel engine, and turn up the fuel pump so that it belches toxic black smoke into the air."

 

[This is The End]

How can we know if we have no actual evidence of it ever happening before?

You mean like Venus?

 

[Tero]

Oh no, not this again. Al Gore is not a scientist.

Buy a book.
https://global.oup.com/academic/pro...ort-introduction-9780198719045?cc=us&lang=en&

 

[Pixel42]

The OP hasn't been back to the forum for a week, so either he got the answers he was looking for or he didn't like the answers he did get. In case he comes back, or anyone else is interested, here's a link to a course I've just started called Our Earth's Future:

https://www.coursera.org/learn/earth-climate-change/home/week/1

It's five weeks but each week is only a couple of hours' study. I've only done the first week so far but I can already recommend it. The course is run by the American Museum of Natural History and contributors include Gavin Schmidt.