The Science of Climate Change Explained: Facts, Evidence and Proof -- Definitive answers to the big questions.

Well, this is biting off a lot to chew. But it does address many of the issues that I see discussed on EnergyCentral.com. (Non-subscribers get at least a few free articles per month, though you may have to give your e-mail address.)  The article provides quite a few impressive references. If nothing else, it helps establish that if someone reads this and still insists that there is no evidence that GHG emissions are causing climate change, and that we should do something about it, then there is not much hope that anything will convince skeptics.  That surely is the case with some skeptics. But I hope it is not all.

If I understand correctly, the photo montage on the cover of the article illustrates many of the sources of data on which the conclusions are based. It seems to cover most or all of the physical and intellectual areas where independent observations suggest that climate change is occurring and why. 

I really did not think it was necessarily worthwhile to share this article. But that changed when I saw this on Energy Central today which, frankly, shocked me: "There is no evidence that CO2 is responsible for climate change, though that is the consensus hypothesis. There is no evidence that climate change is a crisis, or an existential threat."

Well, sorry.  I cannot leave that unchallenged. That is just not true.  The evidence may not be 100% conclusive. But there is very good evidence. This is an effort to change your mind.  By all means, refute the evidence. At least you have to admit that you should either refute it, or stop saying it.

To be clear, this first quote from the article is not evidence. It is a relatively simple, basic fact of life on our earth:

"Greenhouse gases like water vapor and carbon dioxide serve an important role in the climate. Without them, Earth would be far too cold to maintain liquid water and humans would not exist!

Here’s how it works: the planet’s temperature is basically a function of the energy the Earth absorbs from the sun (which heats it up) and the energy Earth emits to space as infrared radiation (which cools it down). Because of their molecular structure, greenhouse gases temporarily absorb some of that outgoing infrared radiation and then re-emit it in all directions, sending some of that energy back toward the surface and heating the planet. Scientists have understood this process since the 1850s."

This is one piece of evidence for how greenhouse gas emissions affect the atmosphere:

"We know based on the physics described above that this should cause the climate to warm. We also see certain telltale “fingerprints” of greenhouse warming. For example, nights are warming even faster than days because greenhouse gases don’t go away when the sun sets. And upper layers of the atmosphere have actually cooled, because more energy is being trapped by greenhouse gases in the lower atmosphere.

We also know that we are the cause of rising greenhouse gas concentrations — and not just because we can measure the CO2 coming out of tailpipes and smokestacks. We can see it in the chemical signature of the carbon in CO2.

Carbon comes in three different masses: 12, 13 and 14. Things made of organic matter (including fossil fuels) tend to have relatively less carbon-13. Volcanoes tend to produce CO2 with relatively more carbon-13. And over the last century, the carbon in atmospheric CO2 has gotten lighter, pointing to an organic source.

We can tell it’s old organic matter by looking for carbon-14, which is radioactive and decays over time. Fossil fuels are too ancient to have any carbon-14 left in them, so if they were behind rising CO2 levels, you would expect the amount of carbon-14 in the atmosphere to drop, which is exactly what the data show.

It’s important to note that water vapor is the most abundant greenhouse gas in the atmosphere. However, it does not cause warming; instead it responds to it. That’s because warmer air holds more moisture, which creates a snowball effect in which human-caused warming allows the atmosphere to hold more water vapor and further amplifies climate change. This so-called feedback cycle has doubled the warming caused by anthropogenic greenhouse gas emissions."

Here is another piece of evidence, though, if you have not heard this before, you´re just not paying attention.

"Bubbles of ancient air trapped in ice show that, before about 1750, the concentration of carbon dioxide in the atmosphere was roughly 280 parts per million. It began to rise slowly and crossed the 300 p.p.m. threshold around 1900. CO2 levels then accelerated as cars and electricity became big parts of modern life, recently topping 420 p.p.m. The concentration of methane, the second most important greenhouse gas, has more than doubled. We’re now emitting carbon much faster than it was released 56 million years ago."

I am guessing that the skeptics most often use "the models are not accurate" anodyne to persuade us to relax; it is too complicated for us humans to measure.  This article takes that on:

"Climate change is often cast as a prediction made by complicated computer models. But the scientific basis for climate change is much broader, and models are actually only one part of it (and, for what it’s worth, they’re surprisingly accurate)."

Please have a look at the references. Believe me, no one will call you a fascist if you read the article, no matter what you think afterwards.

Also, there´s the old, and often misused "correlation is not causation" refutation.

"Another study put it this way: The odds of current warming occurring without anthropogenic greenhouse gas emissions are less than 1 in 100,000."

Here is one sentence from the paper, published in 2014:

"December 2013 was the 346th consecutive month where global land and ocean average surface temperature exceeded the 20th century monthly average, with February 1985 the last time mean temperature fell below this value. Even given these and other extraordinary statistics, public acceptance of human induced climate change and confidence in the supporting science has declined since 2007."

So, do you want us to depend on the one chance in a hundred thousand that climate change is not caused by greenhouse gas emissions? If so, I suggest you buy a lottery ticket.

So, here are the correlating data:

"For at least the last 800,000 years, atmospheric CO2 concentrations oscillated between about 180 parts per million during ice ages and about 280 p.p.m. during warmer periods, as carbon moved between oceans, forests, soils and the atmosphere. These changes occurred in lock step with global temperatures, and are a major reason the entire planet warmed and cooled during glacial cycles, not just the frozen poles."

"Today, however, CO2 levels have soared to 420 p.p.m. — the highest they’ve been in at least three million years. The concentration of CO2 is also increasing about 100 times faster than it did at the end of the last ice age. This suggests something else is going on, and we know what it is: Since the Industrial Revolution, humans have been burning fossil fuels and releasing greenhouse gases that are heating the planet now (see Question 5 for more details on how we know this, and Questions 4 and 8 for how we know that other natural forces aren’t to blame)."

 Things have changed a bit since the 2014 paper was published: More scientists believe the data and so do the majority of the US population:

"Currently, more than 97 percent of publishing climate scientists agree on the existence and cause of climate change (as does nearly 60 percent of the general population of the United States)."

These are the topics covered in the article:

• How do we know climate change is really happening?
• How much agreement is there among scientists about climate change?
• Do we really only have 150 years of climate data? How is that enough to tell us about centuries of change?
• How do we know climate change is caused by humans?
• Since greenhouse gases occur naturally, how do we know they’re causing Earth’s temperature to rise?
• Why should we be worried that the planet has warmed 2°F since the 1800s?
• Is climate change a part of the planet’s natural warming and cooling cycles?
• How do we know global warming is not because of the sun or volcanoes?
• How can winters and certain places be getting colder if the planet is warming?
• Wildfires and bad weather have always happened. How do we know there’s a connection to climate change?
• How bad are the effects of climate change going to be?
• What will it cost to do something about climate change, versus doing nothing?

At the very least, it will be some interesting reading. Do you have to buy into it all? Of course not.  But the conclusion is difficult to escape.  Even if you don´t buy it, I don´t see how you can simply dismiss it.

If you wish, skip to the last section on costs. The case is made that it will cost more to not do something than to do something to reduce the risk.

No one is saying that they have the authoritative answer to that one.  This is the issue with the greatest uncertainty in the whole discussion. But there are some educated guesses:

To do something:

"Estimates of the cost vary widely. One recent study found that keeping warming to 2 degrees Celsius would require a total investment of between $4 trillion and $60 trillion, with a median estimate of $16 trillion, while keeping warming to 1.5 degrees Celsius could cost between $10 trillion and $100 trillion, with a median estimate of $30 trillion. (For reference, the entire world economy was about $88 trillion in 2019.)"

Now, the estimates for not doing something:

"Moody’s Analytics estimates that even 2 degrees Celsius of warming will cost the world $69 trillion by 2100, and economists expect the toll to keep rising with the temperature. In a recent survey, economists estimated the cost would equal 5 percent of global G.D.P. at 3 degrees Celsius of warming (our trajectory under current policies) and 10 percent for 5 degrees Celsius. Other research indicates that, if current warming trends continue, global G.D.P. per capita will decrease between 7 percent and 23 percent by the end of the century — an economic blow equivalent to multiple coronavirus pandemics every year. And some fear these are vast underestimates."

As for "fascism", it is hardly autocratic for the neighborhood association to mandate that it is illegal for us to throw our garbage over the fence into our neighbors´ yards, as we find better ways to both reduce the quantity and toxicity of our garbage  and better ways to dispose of what remains.

Sure, many of us Seniors can pretty much live out the rest of our lives in bliss, albeit often ignorant bliss, knowing that we will be gone by the time the bill is due (unless, I suggest, if you live in Florida, or Alaska).

The scientists who provide the data for this article are not hucksters.  They are not writers or editors of the New York Times.  They are not part of a conspiracy. They may not be 100% right. But, they are the best we´ve got.  And they are good. Don´t you owe it to your grandchildren to take it seriously?

One thing is for sure: Things will not stay the same.  They never have. Never will. As Yogi Berra said: "The future ain’t what it used to be."