Guest post by David Middleton
The current draft of the report can be found here:
Fourth National Climate Assessment (NCA4), Fifth-Order Draft (5OD)
After a cursory review of the document, a few items are worth noting.
Representative Concentration Pathways (RCPs)
A third difference between the RCPs and previous scenarios is that while none of the SRES scenarios included a scenario with explicit policies and measures to limit climate forcing, all of the three lower RCP scenarios (2.6, 4.5, and 6.0) are climate-policy scenarios. At the higher end of the range, the RCP8.5 scenario corresponds to a future where carbon and methane emissions continue to rise as a result of fossil fuel use, albeit with significant declines in emission growth rates over the second half of the century (Figure 4.1), significant reduction in aerosols, and modest improvements in energy intensity and technology (Riahi et al. 2011). Atmospheric carbon dioxide levels for RCP8.5 are similar to those of the SRES A1fi scenario: they rise from current-day levels of 400 up to 936 parts per million (ppm). CO2 16 -equivalent levels (including emissions of other non-CO2 17 greenhouse gases, aerosols, and other substances that affect climate) reach more than 1200 ppm by 2100, and global temperature is projected to increase by 5.4°–9.9°F (3°–5.5°C) by 2100 relative to the 1986–2005 average. RCP8.5 reflects the upper range of the open literature on emissions, but is not intended to serve as an upper limit on possible emissions nor as a business-as-usual or reference scenario for the other three scenarios.
Page 190
First the good news:
“RCP8.5… is not intended to serve as… a business-as-usual or reference scenario.”
That said, a text search of the document returned the following:
| Representative Concentration Pathways | |
| Scenario | Occurrences |
| RCP2.6, RCP 2.6 | 17 |
| RCP4.5, RCP 4.5 | 32 |
| RCP8.5, RCP 8.5 | 75 |
One might think that the business-as-usual or reference scenario would be the most commonly referenced scenario. However, RCP 8.5 is referenced more than all the other scenarios combined. While RCP 6.0, “a mitigation scenario, meaning it includes explicit steps to combat greenhouse gas emissions (in this case, through a carbon tax)” which most closely matches “business-as-usual,” is only referenced once.
A Sampling of Key Findings
3. Detection and Attribution of Climate Change
Key Findings
1. The likely range of the human contribution to the global mean temperature increase over the period 1951–2010 is 1.1° to 1.4°F (0.6° to 0.8°C), and the central estimate of the observed warming of 1.2°F (0.65°C) lies within this range (high confidence). This translates to a likely human contribution of 93%–123% of the observed 1951–2010 change. It is extremely likely that more than half of the global mean temperature increase since 1951 was caused by human influence on climate (high confidence). The likely contributions of natural forcing and internal variability to global temperature change over that period are minor (high confidence).
Page 160
Over the past 2,000 years, the average temperature of the Northern Hemisphere has exceeded natural variability (defined as two standard deviations from the pre-1865 mean) three times: 1) the peak of the Medieval Warm Period 2) the nadir of the Little Ice Age and 3) since 1998. Human activities were unlikely to have been the cause of the first two deviations. 70% of the warming since the early 1600’s clearly falls within the range of natural variability.
On a climatology basis, the modern warming only exceeds Common Era pre-industrial natural variability by a maximum of 0.216° C
6. Temperature Changes in the United States
KEY FINDINGS
1. Average annual temperature over the contiguous United States has increased by 1.2°F (0.7°C) for the period 1986–2016 relative to 1901–1960 and by 1.8°F (1.0°C) based on a linear regression for the period 1895–2016 (very high confidence). Surface and satellite data are consistent in their depiction of rapid warming since 1979 (high confidence). Paleo-temperature evidence shows that recent decades are the warmest of the past 1,500 years (medium confidence).
Page 267
“Medium confidence” is equivalent to a Scientific Wild-Ass Guess (SWAG).
The lame-stream media took “suggestive evidence, limited consistency, models incomplete, methods emerging, competing schools of thought and turned it into a statement of fact:
Just as troubling were draft findings destined for the quadrennial National Climate Assessment. Scientists from 13 federal agencies found that a rapid rise in temperatures since the 1980s in the United States represents the warmest period in 1,500 years.
A “medium confidence” Mannian Hockey Stick became: “Scientists from 13 federal agencies found that a rapid rise in temperatures since the 1980s in the United States represents the warmest period in 1,500 years.”
They based this assertion on one hockey-stick climate reconstruction, Mann et al., 2008.
None of the spectrally consistent reconstructions (Moberg, Esper, Ljungqvist, etc. were cited)… I wonder why?
So, what would it mean, if the reconstructions indicate a larger (Esper et al., 2002; Pollack and Smerdon, 2004; Moberge t al., 2005) or smaller (Jones et al., 1998; Mann et al., 1999) temperature amplitude? We suggest that the former situation, i.e. enhanced variability during pre-industrial times, would result in a redistribution of weight towards the role of natural factors in forcing temperature changes, thereby relatively devaluing the impact of anthropogenic emissions and affecting future predicted scenarios. If that turns out to be the case, agreements such as the Kyoto protocol that intend to reduce emissions of anthropogenic greenhouse gases, would be less effective than thought.
12. Sea Level Rise
KEY FINDINGS
1. Global mean sea level (GMSL) has risen by about 7–8 inches (about 16–21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993 (very high confidence). Human-caused climate change has made a substantial contribution to GMSL rise since 1900 (high confidence), contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years (medium confidence).
2. Relative to the year 2000, GMSL is very likely to rise by 0.3–0.6 feet (9–18 cm) by 2030, 0.5–1.2 feet (15–38 cm) by 2050, and 1 to 4 feet (30–130 cm) by 2100 (very high confidence in lower bounds; medium confidence in upper bounds for 2030 and 2050; low confidence in upper bounds for 2100). Future emissions pathways have little effect on projected GMSL rise in the first half of the century, but significantly affect projections for the second half of the century (high confidence). Emerging science regarding Antarctic ice sheet stability suggests that, for high emission scenarios, a GMSL rise exceeding 8 feet (2.4 m) by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed. Regardless of emissions pathway, it is extremely likely that GMSL rise will continue beyond 2100 (high confidence).
Page 493
“Global mean sea level (GMSL) has risen by about 7–8 inches (about 16–21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993 (very high confidence)”… And?
Sea level has been rising at a secular rate of about 1.9 mm/yr since the end of neoglaciation (~1860 AD).
About 3 inches of sea level rise has occurred since 1993. About 4 inches of sea level rise occurred from 1930-1950. There was very little sea level rise from 1951-1992.
“Human-caused climate change has made a substantial contribution to GMSL rise since 1900 (high confidence)”… Based on what???
“Contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years (medium confidence)”… Another SWAG based on another hockey stick (Kopp et al., 2016).
“Relative to the year 2000, GMSL is very likely to rise by 0.3–0.6 feet (9–18 cm) by 2030, 0.5–1.2 feet (15–38 cm) by 2050, and 1 to 4 feet (30–130 cm) by 2100 (very high confidence in lower bounds; medium confidence in upper bounds for 2030 and 2050; low confidence in upper bounds for 2100).”
At least they get this one somewhat correct.
“Relative to the year 2000, GMSL is very likely to rise by… 1 to 4 feet (30–130 cm) by 2100 (very high confidence in lower bounds… low confidence in upper bounds for 2100)”
Sea level is very likely to rise a bit less than 1 foot over the remainder of this century.
Figure ES.8b is simply bat schist crazy.
And, of course, the lame-stream media turns this into…
The report, by more than 450 scientists from 60 nations, also found that greenhouse gases in the atmosphere and global sea levels are at their highest levels on record.
It all depends on when you start the record.
Life in the Adjustocene
Yesterday, I authored a post about NCA3’s model projections and I noted that the observations had falsified their models…
Well, it appears that NCA4 will address this issue by adjusting the observations to match the models…
They adjusted the observations to match the model in the current draft report.
NCA4 shows the observations tracking the model-mean prior to the 2016 El Niño and then spiking above the mean during it. Nick Stokes provided the following image in one of his very astute comments:
Conclusions
NCA4 paints a picture of the climate basically behaving within the general bounds of Late Holocene natural variability, accompanied by lots of rhetoric about being certain that humans have caused at least half of whatever happened since 1950…
“Same as it ever was”…
According to this summary, the method of climate change attribution used in the report seems to be more primitive than was acceptable within the IPCC detection and attribution science community in the 1990s.
Back then, Hansen’s 1988 attribution claim was rejected because it was primarily based on instrumental-based GMT standard deviation from a norm to find the abnormality (and so attribution) to 99% likelihood. This attribution claim was roundly rejected by the scientific community, including by the authors of IPCC first assessment (Wigley and Barnett), because it was not an adequate way to determine deviation from natural variability. In fact, Hansen’s method is a strategy used in a situation of absolute ignorance: to say that things will stay the same except varying in a purely random way (eg it has been raining the last few days, so it will probably rain on tomorrow’s parade). Even in situations of almost absolute ignorance there are those who have argued that, while the presumption of normal distribution over any other presumption is convenient, the case for this presumption is weak (eg., John Maynard Keynes in 1921).
Even on this presumption: to acknowledge MWP and LIA as two natural events at the limits of normal distribution within such a short time frame and to still use this method to show that this third one is unnatural — this is even more silly. In the 1980s and 1990s it was generally agreed that warming ‘pattern analysis’ was more suitable to the task of attribution, and so for the IPCC second assessment Santer used this method to make the case. When, using the short instrumental record, this was shown to fail (missing ‘hotspot’, not much distinction between CO2-driven warming and other drivers of warming patterns, no pre-emissions benchmark etc.), it has pretty much been abandoned as the basic for attribution claims. This is why the hockey stick proxy+instrument GMT 1000-year graph was so important for the IPCC third assessment. There, the anomaly of recent decades was so wildly out of range that one could hardly question that something strange and unnatural is going on.
Now, in this report and perhaps elsewhere, with the measured retreat from the Hockey Stick, it seems we are back very close to Hansen in 1988, only without the furor in the scientific community that occurred back then.
Port Arthur (Tasmania) 1841 benchmark mean tide mark in geologically stable rock shows about 3cm rise.
Real inconvenient data!
Sea level DOWN TREND for MSM’s doomed islands of NAURU, KIRIBATI and VANUATU.
Very inconvenient data from automatic tide gauges verified by high-resolution satellite altimeter measurements.
Antarctic sea levels in long term DOWN TREND.
Wait . . . isn’t that where billions of tonnes of ice are turning to water?
Extremely inconvenient data so yep the UN stopped AU Gov publication between 2008 – 2010.
AAD data did not support IPCC’s warnings of impending catastrophic sea level rise.
You guessed it . . . to this day AAD sea-level data remains un-published.
Fraudsters all!
Attribution in models is a circular argument. The models don’t prove the ascertion because the attributed to human warming is an input.
👍🏿
“with about 3 of those inches (about 7 cm) occurring since 1993 (very high confidence).”
Sorry, the satellite altimetry record was revised downward from an average of 3.2 mm/yr to 2.4 mm/yr. That reduces 7 cm to 5.2 cm and 3″ to 2.2″. And it should reduce the confidence level from very high to perhaps likely. The problem with satellite altimetry (which makes thousands of measurements a day) is not noise, but systematic error.
You are correct!
Single figure representing a temperature of the earth tells anyone NOTHING about the climate and how it is changing. It may get warmer in the tropic while cooling at the poles and the ‘global temperature’ could stay the same.
Climate and climate effects are only ever regional or zonal.
Note: these projections on future CO2 concentrations are a fairy tale, nothing more.
With an increase of CO2 levels in the atmosphere from 280 to 400ppm, natural uptake (CO2 sinks) has increased by roughly 20 Gt per year. As compared to annual anthropogenic emissions of about 36Gt this is a major factor, strongly flattening the Keeling Curve. Otherwise we might see an annual rise of 4.5ppm per year, rather than just 2ppm.
The science of doom wants to suggest that CO2 sinks will stop their work in the near future for … well who knows? Like we have been evil and diserve it or so.
Those 20 Gt are indeed a massive figure, but are easily dwarfed by some 700Gt in natural Co2 turnover. So if we compare these figures, natural uptake of CO2 has only increased by 20/700 = 3%, which is a very modest figure as compared to a 43% increase of atmospheric Co2 (400/280 – 1 = 0.43). This relation should well demonstrate how natural CO2 sinks have yet of of healthy potential to work even stronger in the future.
So the question is, how strongly CO2 sinks will work once we achieve like 500, 700, or even 900ppm, as suggested? If we would suggest a linear relation, at 700ppm it would yield (700 – 280) / 120 * 20 = 87Gt. Sure this may be over optimistic, and more likely we will see diminishing returns. But 50Gt might be a reasonable guess. At that point Co2 levels in the atmosphere would be 2.5times the preindustrial level, with natural uptake only increasing by 50/700 = 7%.
So only to maintain a level of 700ppm, mankind would need to emit 50Gt per y<ear. Even though that might well be possible, an additional increase of 5ppm p.a. as indicated, would require another 40Gt of CO2 emissions, totaling that figure to 90Gt. This figure might be hard to achieve.
If the world held a population of 10 Billion by 2100, that would correspond to 9t per capita. By comparison: the EU is emitting 6.8t per capita today.
For these reasons, the "RCP 6.0" scenario seems highly unlikely, almost impossible to achieve, even if we were seeking to maximize our CO2 output. "RCP 4.5" looks more like a realistic base scenario in the absence of "climate saving", while "RCP 8.5" is pure fiction.
Btw. you might not have seen this yet. I wanted to know for some time, how well CO2 sinks scale with the elevation of CO2 in the atmosphere. So I took the amount of CO2 in the atmosphere according to the Keeling curve minus the natural level. By now we have added over 900Gt of CO2 to the atmosphere.
The other part of course was about determining the effect of CO2 sinks over a longer period. So I took data on global CO2 emissions and subtracted the increase in atmospheric CO2 levels from it. Even though I smoothed the chart a bit by averaging 3 years, it is still pretty erratic.That should not be much of a surprise, as there are strong variations in the mighty natural CO2 cycle (vulcanic activity, better or worse years for plant growth in the northern hemisphere, El Nino and so on..).
Yet the outcome is quite conclusive. CO2 sinks scale almost perfectly with the increase of atmospheric CO2. In fact this relation seems to work almost linearly, and they show no sign of weakening whatsoever.
http://i736.photobucket.com/albums/xx10/Oliver25/Keeling%20vs.%20CO2%20sinks_2.png
(Note: I multiplied the effect of CO2 sinks by 50 to match the scale)
From the article: “Over the past 2,000 years, the average temperature of the Northern Hemisphere has exceeded natural variability (defined as two standard deviations from the pre-1865 mean) three times: 1) the peak of the Medieval Warm Period 2) the nadir of the Little Ice Age and 3) since 1998.”
Hansen’s U.S. surface temperature chart (before bastardization) shows the 1930’s as being 0.5C hotter than 1998.
RC- 8.5 = 960-1400ppm of CO2. (I have seen 1400 before. Did they lower it?)
We have gotten 100ppm in 70 years. We are growing at 2ppm/year. In 80 years we get 160ppm at current rates. From the 400 we are at now it is 560-570 not 960. To get to 960 would require 550ppm in 80 years = 7ppm/year = 3.5 times the current rate.
Granted CO2 production is growing but over the next century energy use will peak and population will peak and we will get more efficient. It is extremely unlikely we will continue to see exponential energy for the rest of the century or that all that energy would be from fossil fuels. Thus rcp8.5 at 960 or 1400 is absurd.
It requires an exponential assumption that is the reason all predictions of the future end up failing. From Malthus to Club of Rome the main problem has been the rate of technology growth.
In the last century we went from 2,000,000 per year dying from natural disasters to 40,000 by the end of the century and 20,000 by the next decade. Harvey has killed 5 people so far. There are sure to be more but we are getting so good at so many things simultaneously any prediction 80 years hence is absurd.
In 80 years we will probably be traveling at near zero cost and energy in 5,000 mph tunnels and our electronics will be so efficient and food production that we will probably be using less energy than today overall and none of it will come from fossil fuels. We will do this without justice warriors.