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Record surge in atmospheric CO2 seen in 2016

Brad H

Record surge in atmospheric CO2 seen in 2016
By Matt McGrath Environment correspondent
Record surge in atmospheric CO2 in 2016

Concentrations of CO2 in the Earth's atmosphere surged to a record high in 2016, according to the World Meteorological Organization (WMO).

Last year's increase was 50% higher than the average of the past 10 years.

Researchers say a combination of human activities and the El Niño weather phenomenon drove CO2 to a level not seen in 800,000 years.

Scientists say this risks making global temperature targets largely unattainable.

This year's greenhouse gas bulletin produced by the WMO, is based on measurements taken in 51 countries. Research stations dotted around the globe measure concentrations of warming gases including carbon dioxide, methane and nitrous oxide.

The figures published by the WMO are what's left in the atmosphere after significant amounts are absorbed by the Earth's "sinks", which include the oceans and the biosphere.

Climate change: a guide

A brief history of Earth's CO2

Global Change Calculator

2016 saw average concentrations of CO2 hit 403.3 parts per million, up from 400ppm in 2015.

"It is the largest increase we have ever seen in the 30 years we have had this network," Dr Oksana Tarasova, chief of WMO's global atmosphere watch programme, told BBC News.

"The largest increase was in the previous El Niño, in 1997-1998 and it was 2.7ppm and now it is 3.3ppm, it is also 50% higher than the average of the last ten years."

El Niño impacts the amount of carbon in the atmosphere by causing droughts that limit the uptake of CO2 by plants and trees.

Emissions from human sources have slowed down in the last couple of years according to research, but according to Dr Tarasova, it is the cumulative total in the atmosphere that really matters as CO2 stays aloft and active for centuries.

Over the past 70 years, says the report, the increase in CO2 in the atmosphere is nearly 100 times larger than it was at the end of the last ice age.

Rapidly increasing atmospheric levels of CO2 and other gases have the potential, according to the study to "initiate unpredictable changes in the climate system... leading to severe ecological and economic disruptions."

The study notes that since 1990 there has been a 40% increase in total radiative forcing, that's the warming effect on our climate of all greenhouse gases.

"Geological-wise, it is like an injection of a huge amount of heat," said Dr Tarasova.

"The changes will not take ten thousand years like they used to take before, they will happen fast - we don't have the knowledge of the system in this state, that is a bit worrisome!"

According to experts, the last time the Earth experienced a comparable concentration of CO2 was three to five million years ago, in the mid-Pliocene era. The climate then was 2-3C warmer, and sea levels were 10-20m higher due to the melting of Greenland and the West Antarctic ice sheets.

Other experts in the field of atmospheric research agreed that the WMO findings were a cause for concern.

"The 3ppm CO2 growth rate in 2015 and 2016 is extreme - double the growth rate in the 1990-2000 decade," Prof Euan Nisbet from Royal Holloway University of London told BBC News.

"It is urgent that we follow the Paris agreement and switch rapidly away from fossil fuels: there are signs this is beginning to happen, but so far the air is not yet recording the change."

Another concern in the report is the continuing, mysterious rise of methane levels in the atmosphere, which were also larger than the average over the past ten years. Prof Nisbet says there is a fear of a vicious cycle, where methane drives up temperatures which in turn releases more methane from natural sources.

"The rapid increase in methane since 2007, especially in 2014, 2015, and 2016, is different. This was not expected in the Paris agreement. Methane growth is strongest in the tropics and sub-tropics. The carbon isotopes in the methane show that growth is not being driven by fossil fuels. We do not understand why methane is rising. It may be a climate change feedback. It is very worrying."

The implications of these new atmospheric measurements for the targets agreed under the Paris climate pact, are quite negative, say observers.

"The numbers don't lie. We are still emitting far too much and this needs to be reversed," said Erik Solheim, head of UN Environment.

"We have many of the solutions already to address this challenge. What we need now is global political will and a new sense of urgency."

The report has been issued just a week ahead of the next instalment of UN climate talks, in Bonn. Despite the declaration by President Trump that he intends to take the US out of the deal, negotiators meeting in Germany will be aiming to advance and clarify the rulebook of the Paris agreement.

Brad H

Here is an overview/reference to the sources that was provided by "robert scribbler" from his comments section at: Whitefish Puerto Rico Contract Cancelled, Now How About Letting Renewable Industry Leaders Step in?

>>We haven’t mentioned it in a little while. So I’ll give a brief refresher here:
1. Present atmospheric CO2 levels approaching an average of 410 ppm represent a long term level of warming in the range of around 2.1 to 3.5 C.
2. Present atmospheric ghg levels in the range of 491 ppm CO2e represent a long term level of warming in the range of 3.2 to 4.2 C.
3. These ranges represent 1.6 to 2.1 C warming this Century even if they just remain stable.
4. Reduction of present atmospheric greenhouse gas loading is necessary to remove risk that warming will exceed 1.5 and 2.0 C thresholds this Century.
5. A warming climate makes this more difficult due to the fact that the Earth system is likely to contribute a feedback of between 10 percent and 30 percent carbon emissions relative to the present annual human based fossil fuel emission (primary source) going forward over the next 80 or so years<<

/ October 31, 2017
Brad —

This is based on my analysis and interpretation of active ghg monitors, Earth System climate sensitivity, climate system inertia, climate system feedbacks, and paleoclimate science data:

REF 1.1:

Peak CO2 in 2018 will be in the range of 411 to 412 min CO2 will be 405 to 406. Average will range from 408 to 409 during 2018 at MLO. 2019 will hit between 410 ppm to 411 ppm average in that monitor. Global monitor will lag by a year or so.

REF 1.2:

Paleoclimate data indicates that past CO2 levels in this range produced long term warming near 3 C. I identify a rough range of 2.1 to 3.5 C given uncertainty in the proxy data.

Pliocene temperatures: 6.3.2 What Does the Record of the Mid-Pliocene Show? - AR4 WGI Chapter 6: Palaeoclimate

Average CO2 at that time was 390 ppm with temps ranging from 2-3 C warmer than 1880s.

Miocene temperatures: Why the Miocene Matters (and doesn’t) Today

Average CO2 during middle Miocene ranged from 3-4 C with CO2 ranging from 400 to 500 ppm during the middle miocene climate optimum.

See also: Miocene - Wikipedia

Worth noting that ranges closer to 400 ppm CO2 showed closer to 3 C long term warming.

REF 2.1: 491 CO2 equivalent forcing is estimated for 2017 based on this data by NOAA.


NOAA notes that CO2e from all greenhouse gasses during 2016 was 489 ppm. Average gain from CO2 alone nets us 491.2. Other ghg gain might push this a bit higher. La Nina will tend to lower the overall average for a single year. Hence the 491 ppm CO2e estimate for 2017.

REF 2.2:

491 CO2e forcing roughly correlates with the Middle Miocene climate optimum during which global temperatures were as high as 4 C warmer than 1880s values and atmospheric CO2 hit about as high as 500 ppm. The range of 3.2 to 4.2 accounts for uncertainty in the paleoclimate proxy data.

REF 3:

Because warming will tend to lag due to inertia in the climate system, Century levels of warming will be approximately half that of the total long term warming levels. This is not an exact estimate. Just a rough rule of thumb.

Basic global warming science finds that you get about 1/3 of the warming up front, another 1/3 after 1-3 Centuries, and the last 1/3 after more than 500 years or so. This is primarily due to the thermal inertia of the ocean, the ice sheets (which generate increased albedo), and due to water vapor feedback as atmospheric water vapor levels rise due to increased evaporation off a warming ocean.

Climate inertia - Wikipedia

Again, this is a rough rule of thumb based on reported science.

REF 4: Self explanatory given past supports in REF 1 through REF 3.

REF 5: Multiple references. Here is just one:

Carbon feedback from forest soils to accelerate global warming

This is a brief list of references due to time constraint. If you are quoting me or using my comment for an article, I can provide more. But if this is a general inquiry. The background information should suffice.
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David Klein

Hi Brad,

Thanks for the references. That's a lot of information and I'll just comment on some of it.

I think this statement has mistakes:

"NOAA notes that CO2e from all greenhouse gasses during 2016 was 489 ppm. Average gain from CO2 alone nets us 491.2. Other ghg gain might push this a bit higher. La Nina will tend to lower the overall average for a single year. Hence the 491 ppm CO2e estimate for 2017."​

How can the combined total of all GHGs (including CO2) be 489 ppm, but CO2 alone be more than that at 491.2 ppm? There must be a mistake here. I also disagree with this comment:

"Basic global warming science finds that you get about 1/3 of the warming up front, another 1/3 after 1-3 Centuries, and the last 1/3 after more than 500 years or so.​

See for example this 2014 research paper: Maximum warming occurs about one decade after a carbon dioxide emission
and the accompanying instructive video explaining it in layman's terms.

More generally, I don't think that extrapolating correlations between CO2 concentrations and global temperature anomalies of the miocene epoch to the present gives reliable predictions for the future. The world was different then, for example, with different configurations of continents and oceans, orbital parameters, and carbon cycles. The best tools we have to predict the future are global climate models.

The statement, "Present atmospheric CO2 levels approaching an average of 410 ppm represent a long term level of warming in the range of around 2.1 to 3.5 C" seems too high to me. A widely accepted estimate of the climate sensitivity is about 3C, so in other words, a doubling of CO2 concentration is expected to increase the global average temp about 3C over the long term. Here are the basic physics ingredients:

*For each ppm increase of CO2 concentration the atmosphere must absorb 2.12 GtC.

*The relationship between atmospheric CO2 concentration and the corresponding increase in radiative forcing is given (3rd Report IPCC – TAR, table 6.2) by the logarithmic formula: RF = 5.35·ln (C/C0), where RF denotes radiative forcing in W/m2, C is CO2 concentration in parts per million (ppm), C0 is a reference concentration (usually the latter is 280 ppm – the concentration before the industrial revolution).

*Doubling the CO2 concentration (which is equivalent to 3.7 W/m2 increase in radiative forcing) causes temperature increase of 3°C.​

Using this, one can get rough predictions as follows:
Screen Shot 2017-10-31 at 10.28.14 PM.png


Brad H

Thanks for your perspectives and clarifications, David. I know these are all estimates and I appreciate the immense complexity of the modelling that needs to occur to arrive at any numbers. When I see see reports of 20 to 30C above average temperatures in many parts of the Arctic and Antarctic, and the seeming shift to exponential changes indicated at the poles, (just watched a Peter Wadham video) not to mention the multiple other amplifying positive feedbacks, seems it will become increasingly difficult to apply formulas and accurately predict linear changes over time...

David Klein

Hi Brad,

Climate models have done a pretty good job so far of predicting climate. Here are a couple of links that compare measurements with model predictions:

How reliable are climate models? - Skeptical Science
How reliable are climate models?

Climate models are even more accurate than you thought
Climate models are even more accurate than you thought | Dana Nuccitelli

There seems to be a misunderstanding among some climate activists that climate models are limited because they are "linear" and/or that mathematical equations cannot deal with exponential increase. In fact, climate models include nonlinear equations and even the simplest ones are capable of predicting exponential growth (with appropriate inputs). But exponential growth is not always realisitic. Keep in mind that linear growth of global average temperature as a function of total historical emissions is scary enough without baseless claims of exponential growth based only on intuition.