my apologies, my computer skills are very minimal and I don't know whether it is authorised to link but here is the (unabridged) page from:
"Climate Change: Atmospheric Carbon Dioxide
Author:
Rebecca Lindsey
September 19, 2019
The global average atmospheric carbon dioxide in 2018 was 407.4 parts per million (
ppm for short), with a range of uncertainty of plus or minus 0.1 ppm. Carbon dioxide levels today are higher than at any point in at least the past 800,000 years.
<p><img data-fr-image-pasted="true" alt="graph of carbon dioxide over the past 800,000 years, showing glacials and interglacials and how the 2018 CO2 level compares" title="Carbon dioxide over the past 800,000 years" data-delta="18" data-fr-src="
https://www.climate.gov/sites/default/files/paleo_CO2_2018_620.gif" width="620" height="266"><br></p>
Atmospheric carbon dioxide concentrations in parts per million (ppm) for the past 800,000 years, based on EPICA (ice core) data. The peaks and valleys in carbon dioxide levels track the coming and going of ice ages (low carbon dioxide) and warmer interglacials (higher levels). Throughout these cycles, atmospheric carbon dioxide was never higher than 300 ppm; in 2018, it reached 407.4 ppm (black dot). NOAA Climate.gov, based on EPICA Dome C
data (Lüthi, D., et al., 2008) provided by NOAA NCEI Paleoclimatology Program.
In fact, the last time the atmospheric CO2 amounts were this high was more than 3 million years ago, when temperature was 2°–3°C (3.6°–5.4°F) higher than during the pre-industrial era, and sea level was 15–25 meters (50–80 feet) higher than today.
Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over the span of many millions of years; we are returning that carbon to the atmosphere in just a few hundred years.
Squeeze or stretch the graph in either direction by holding the Shift key while you click and drag. The bright red line (
source data) shows monthly average carbon dioxide at NOAA's Mauna Loa Observatory on Hawai'i in parts per million (ppm): the number of carbon dioxide molecules per million molecules of dry air. Over the course of the year, values are higher in Northern Hemisphere winter and lower in summer. The dark red line shows the annual trend, calculated as a 12-month rolling average.
According to the
State of the Climate in 2018 report from NOAA and the American Meteorological Society, global atmospheric carbon dioxide was 407.4 ± 0.1 ppm in 2018, a new record high. That is an increase of 2.5 ± 0.1 ppm from 2017, similar to the increase of 2.2 ± 0.1 ppm between 2016 and 2017.
In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.6 ± 0.1 ppm per year. Over the past decade, however, the growth rate has been closer to 2.3 ppm per year. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.
Why carbon dioxide matters
Carbon dioxide is a
greenhouse gas: a gas that absorbs heat. Warmed by sunlight, Earth’s land and ocean surfaces continuously radiate thermal infrared energy (heat). Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb that heat and release it gradually over time, like bricks in a fireplace after the fire goes out. Without this natural
greenhouse effect, Earth’s average annual temperature would be below freezing instead of close to 60°F. But increases in greenhouse gases have tipped the Earth's energy budget out of balance, trapping additional heat and raising Earth's average temperature.
Carbon dioxide is the most important of Earth’s
long-lived greenhouse gases. It absorbs less heat per molecule than the greenhouse gases methane or nitrous oxide, but it’s more abundant and it stays in the atmosphere much longer. And while carbon dioxide is less abundant and less powerful than water vapor on a molecule per molecule basis, it absorbs wavelengths of thermal energy that water vapor does not, which means it adds to the greenhouse effect in a unique way. Increases in atmospheric carbon dioxide are responsible for about two-thirds of the total energy imbalance that is causing Earth's temperature to rise.
<p><img data-fr-image-pasted="true" alt="stacked area graph showing the relative contribution of all the gases that cause global warming" title="Greenhouse gases relative 1990 amounts" data-delta="19" data-fr-src="
https://www.climate.gov/sites/default/files/aggi_stackedarea_1979-2018_620.jpg" width="620" height="340"><br></p>
(
left vertical axis) The heating imbalance in watts per square meter relative to the year 1750 caused by all major human-produced greenhouse gases: carbon dioxide, methane, nitrous oxide, chlorofluorocarbons 11 and 12, and a group of 15 other minor contributors. Today's atmosphere absorbs about 3 extra watts of incoming solar energy over each square meter of Earth's surface. According to NOAA's Annual Greenhouse Gas Index (
right axis) the combined heating influence of all major greenhouse gases has increased by 43% relative to 1990. NOAA Climate.gov graph, based on
data from NOAA ESRL.
Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH. Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called
ocean acidification.
A drop of 0.1 may not seem like a lot, but the pH scale is logarithmic; a 1-unit drop in pH means a tenfold increase in acidity. A change of 0.1 means a roughly 30% increase in acidity. Increasing acidity interferes with the ability of marine life to extract calcium from the water to build their shells and skeletons.
<p><img data-fr-image-pasted="true" data-delta="11" data-fr-src="
https://www.climate.gov/sites/default/files/pteropod_comparison_620.jpg" width="620" height="337" alt="" title=""><br></p>
(
left) A healthy ocean snail has a transparent shell with smoothly contoured ridges. (
right) A shell exposed to more acidic, corrosive waters is cloudy, ragged, and pockmarked with ‘kinks’ and weak spots.
Photoscourtesy Nina Bednarsek, NOAA PMEL.
Past and future carbon dioxide
Natural increases in carbon dioxide concentrations have periodically warmed Earth’s temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in sunlight due to a tiny wobble in Earth’s axis of rotation or in the path of its orbit around the Sun.
That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide—like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere amplified the initial warming.
Based on air bubbles trapped in mile-thick
ice cores (and other paleoclimate evidence), we know that during the ice age cycles of the past million years or so, carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, the global average amount of carbon dioxide was about 280 ppm.
By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. On May 9, 2013, the daily average carbon dioxide measured at Mauna Loa surpassed 400 ppm for the first time on record. Less than two years later, in 2015, the global amount went over 400 ppm for the first time. If global energy demand continues to grow and to be met mostly with fossil fuels, atmospheric carbon dioxide will likely exceed 900 ppm by the end of this century.
"
I am willing to consider that the Sun is a powerful force and has an influence on the Earth, especially if the magnetic shield that has protected her up till now is no longer adequate, but I will not in that case relinquish my belief that the heedless disregard we humans show to the consequences of our actions, such as: almost exclusive reliance on oil, coal & gas for power, the disastrous addition of lead to petrol, the reckless proliferation of plastics and installation of nuclear power as an 'alternative'. All these procedures carry drawbacks that should have prevented their ever taking place, but since they were, we now need to deal with that.
I think we
know this: (taken from a Hopi proverb) You cannot pump what belongs underground all over the surface, saturate the air and unbalance the chemistry, without there being consequences.
No wonder the young are pissed off with us -it looks like the plan is to leave it to them to deal with.
To say that in the far distant past there was also/more of this much CO2, so that it's 'ok' now, is to neglect the point that complex, vulnerable primates were not necessarily around (500+million ya) especially in our numbers, to make records of whether they could tolerate it. This is what concerns people. Trees and insects, even dinosaurs may have thrived (nice wee 'the greenies should like that' comment) but not us. Your denial of this man-made factor and the presentation of a cause (it's the sun) that we can do nothing about, will lead to apathy and despair.
(Good one!?:()
You know, an important point to remember while we are seeking for truths is that in this complex and crowded world, we are bound to meet those with whom we do not agree. But this should not mean we treat them with hostility or just reject their ideas. They may have a point. It is comfortable to mix with only those who think as we do, but we don't grow unless we learn to listen and allow others to think differently.
Alice, it's not clear from this where your quoted source (which I couldn't find) ends, and where your commentary begins, but I'm assuming the latter begins with "I am willing...". For future reference, perhaps you might consider differentiating between your own and quoted text in some way -- I find indenting and italicising it makes it plain.
In case you don't know how to do that (you mention your minimal computer skills), it's easy enough:
a) Highlight the text you want to quote (just hold down your left mouse button and drag over it)
b) Click the icon fifth from the left at the top of the reply box (the one that looks like four lines, each with a dot on the left-hand side)
c) From the drop- down list that appears, click "indent"
d) Whilst the text is still highlighted, click I for Italicise.
e) Finally, click outside the highlighted area and click I again to revert to normal text.
Assuming I'm right about where your commentary starts, one comment
I'd like to make is that not all people who think the brouhaha over global warming is greatly exaggerated are
deniers in the sense that they deny that CO2 has
some effect on global temperatures. Some do, of course, but many don't, and I'm one of the latter. In case you haven't heard the term before, I, and I suspect a number of commentators here fall into the so-called "lukewarmer" category.
You may care to read
the position of a lukewarmer, Matt Ridley. I'm not saying I agree with everything he says, but we're in a similar ball park. There's no doubt in my mind that CO2 has
some effect on global temperatures. The main questions for me are 1) whether
all the extra CO2 is anthropogenic, 2) whether it's catastrophically harmful, and 3) whether it's the principal factor in global warming, of which there's little doubt we've experienced a little in the recent (geologically speaking) past.
For me, one factor to bear in mind is what are termed
climate feedbacks. In and of itself, CO2 has only a marginal effect on global temperature. What's more important is the effect that water vapour, a significantly stronger "greenhouse gas" (that's a misnomer, but I'll let it go for now) has on temperatures. I posted this video earlier, but I'll post it again because it's the most succinct summary of the skeptical case I can find:
Note that the information in the video doesn't come direct from Stefan Molyneux: he's mostly quoting Dr. David M.W. Evans, who
...consulted full time for the Australian Greenhouse Office (now the Department of Climate Change) from 1999 to 2005, and part time 2008 to 2010, modeling Australia's carbon in plants, debris, mulch, soils, and forestry and agricultural products. Evans is a mathematician and engineer, with six university degrees including a PhD from Stanford University in electrical engineering. The area of human endeavor with the most experience and sophistication in dealing with feedbacks and analyzing complex systems is electrical engineering, and the most crucial and disputed aspects of understanding the climate system are the feedbacks. The evidence supporting the idea that CO2 emissions were the main cause of global warming reversed itself from 1998 to 2006, causing Evans to move from being a warmist to a skeptic.
Forgive me if you watched it earlier, but I'm posting it again just in case you didn't. It's message is about feedbacks, and whether or not they amplify the effects of the small warming due to CO2, which latter very few informed people
deny, whichever side of the argument they're on.
You may have experienced feedback when listening to someone playing electric guitar very loudly, which can produce a deafening squeal as the sound from the speakers feeds back into the pickup. This kind of feedback is called
positive, because the output of the system reinforces the input, and this rapidly builds into the highly unstable state that causes the squeal.
Put in simple terms, this sort of thing is what the CAGW people insist is happening. CO2 is raising global temperature slightly, and that is causing ocean temperatures to rise, creating more water vapour (and also CO2 outgassing), which amplifies the initial "signal" (i.e. the initial rise in CO2). If this were true, at some point (although it would be on a longer timescale than the guitar example), the system would run away and there'd eventually be a catastrophic "squeal", so to speak.
Lukewarmers like me maintain that the evidence for catastrophic feedback is sparse; in fact, that the earth is in a state of
homeostasis, with feedbacks constantly operating so as to minimise the instability. Put another way, feedbacks are, on balance,
negative rather than positive. Listen to the video carefully to appreciate the sceptical position. Homeostasis doesn't imply
invariability; there will be
some variability, but the system tends to bring things back closer to equilibrium, unlike what happens with feedback in the case of the guitar.
This is why it's important to consider the long-term (millions of years) concentration of CO2 in the atmosphere. In the past, it's been on the order of
thousands of parts per million, rather than the 300-400 ppm it has been comparatively recently. And a change of even 100ppm over a matter of decades or a century is neither here nor there: we'd have a very long way to go before the earth "squealed". Maybe in the past there have been comparatively large natural perturbations, but always, negative feedbacks of one kind or another have led to an equilibrating tendency. At no time has life been completely eradicated, although during the most extreme perturbations, we've had ice ages and unusually warm periods.
Quite apart from that, there's the question of whether anthropogenic CO2 is
wholly responsible for the recent increase in atmospheric CO2 concentrations. Let us not forget that the earth is still emerging from the little ice age: it's warming up naturally, and has been since before the 20th and 21st centuries. That
has to be the case, since the use of oil and gas didn't ramp up until after the 2nd world war ended. What was causing the warming before then must have been largely natural, and it's highly dubious that it coincidentally ceased around 1945. In my view, it's likely that there's some continuing contribution from natural processes that have led to the gradual rebound from the little ice age.
Whatever those processes are, I think they are making (possibly the main) contribution to increased temperatures and hence increased ocean evaporation and CO2 outgassing. It's a relatively minor equilibrating event when considered in the light of much more profound events that have happened in the past. The mediaeval warm period (which Michael Mann tried to eliminate) and the subsequent little ice age are the result of comparatively minor recent perturbations. By "minor", I'm speaking in the context of much larger previous variations; I'm not speaking in terms of the effect on living beings. Another little ice age right now would be very damaging to humanity, much worse than another mediaeval warm period. Let's hope we aren't headed towards the former, and are heading rather towards a mild temperature increase -- one that's currently said to be 0.8 deg. C since about 1870.
Yes -- only 0.8 deg. C is what all the fuss is about; what has sent some people into a panic, seeing every extreme weather event as evidence for the truth of CAGW. Extreme weather events have always been with us, but there's evidence that they're lessening rather than increasing, and that what's making the difference is
the pattern of human activities in demographic terms:
In this book, Roger Pielke Jr. summarizes those facts to answer the question, “Have disasters become more costly because of human-caused climate change?” Many people do worry that climate change is causing disasters to get worse, but Pielke presents a wealth of data, including the conclusions of the Intergovernmental Panel on Climate Change, to show why such concerns are not supported by the available science.
Unlike the conditions in Iraq prior to the U.S. invasion, the reasons for rising disaster losses are well understood and unlikely to change significantly with new revelations or data.
Why, then, are disaster costs rising? The reasons are apparent: populations continue to grow, the economy and the built environment continue to expand, and people migrate to and concentrate on coastal and flood plains. There are simply more people, and more of the things that people depend on in their lives, in harm’s way.
Moreover, these demographic trends feed continued environmental degradation of highly populated coastal, riverine, and mountainous regions, which in turn exacerbate the consequences of disasters. Most of these trends are further amplified in developing countries. Climate isn’t the only thing that’s changing in our world, and it’s these other changes that are causing disaster losses to increase.
Of course, CAGW proponents don't accept that: they're absolutely convinced that the earth is undergoing catastrophic climate change. It sometimes seems almost as if they
want it to be so. Why? I don't know for sure. Maybe they need to feel right, or ethically superior; maybe they need to hang their existential fears on something they can
blame, or, even better, some
one they can blame. Who better than those who hold a different opinion?
Google "percentage of people believing in climate change" and settle in for a wide range of surveys, none of which are conclusive and some of which are designed to get the desired answers either way.
Read this to see how surveys can be gamed. Fact is, no one knows how many people there are who agree or disagree on the issues: the answers one gets depends on the nature of the questions asked, and how they're asked. But I think it's safe to say that there's widespread disagreement, and that's one reason I think it's so divisive.
It doesn't matter whether or not those being vilified are, personally, very modest "carbon emitters". It doesn't matter whether the vilifiers are personally very profligate emitters; all that matters is who says what -- what side of the fence they are perceived to be on. Spitting venom at people, them, calling them
deniers, as if they're execrable holocaust-denying nazi sympathisers, is par for the course.
The record shows clearly that temperature changes
precede CO2 increases; Al Gore didn't mention this whilst he was aboard the gantry looking at that huge graph. Maybe he didn't know that was the case; but the current CO2 increase may be the
result of, rather than the
principal cause of, warming that primarily occurs through natural processes. The CAGW view may be analogous to the topsy-turvy view of materialists who think matter causes consciousness rather than consciousness causing the appearance of matter.
Frankly, I'm tired of those who categorise people like me into a group that they can more easily identify and despise. Their motivation appears to be a desire to somehow blame us for drawing different conclusions from the data we observe than they do. They want to stereotype us, attribute to us all sorts of opinions and world views that many of us simply don't hold. The impulse is to return the venom, to label/stereotype them in return -- call them snowflakes, bleeding heart liberals or whatever. I have to admit that occasionally I've used the first term myself when I've lost patience with them.
Why, for heaven's sake, can't people calmly
discuss their differences? Why do we seem to live in an era where certain things (global warming, psi, Darwinism, scientism...the list is endless) simply can't be discussed openly? Whence comes all the political correctness and intolerance, all the authoritarianism?
F....d if I know. But what I suspect is that "global warming" isn't really a
cause of anything; it's a
symptom of an underlying malaise in Western society; the perfect vehicle around which to draw the battle lines between two groups: those on the left and those on the right. I don't identify with either group, as it happens. I suppose I'd classify myself as a libertarian with both leanings that might be classified as left, and those that might be classified as right.
The only reason it can work is because of the recondite nature of climate science. It's a perfect obscurer, and proponents either way can easily find evidence to support underlying predilections. We're going nowhere with the argument. Who is right and who is wrong may only be ascertainable with the passage of time. Either the alarmists will prove to be right, or they won't; some point will come when dire predictions will or won't eventuate, and one outcome will be universally accepted. When is that point? 10, 20, 30 years? By the end of the century? Who can say. Meanwhile I and everyone else has to take a position: for, against, undecided, or apathetic.
Maybe in the end we're at a stage we have to go through, unpleasant as it is, before we eventually escape it into something better. Or maybe not;. maybe eventually we'll end up in complete chaos and see the end of Western civilisation altogether... and who knows, maybe that too is something necessary for humanity as a whole.