New paper finds strong evidence the Sun has controlled climate over the past 11,000 years, not CO2

A paper published today in Journal of Atmospheric and Solar-Terrestrial Physics finds a "strong and stable correlation" between the millennial variations in sunspots and the temperature in Antarctica over the past 11,000 years. In stark contrast, the authors find no strong or stable correlation between temperature and CO2 over that same period. 

The authors correlated reconstructed CO2 levels, sunspots, and temperatures from ice-core data from Vostok Antarctica and find

"We find that the variations of SSN [sunspot number] and T [temperature] have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that of T by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO2 and T are neither strong nor stable."

Thus, the well known ~1000 year climate cycle responsible for the Holocene Climate Optimum 6000 to 4000 years ago, the Egyptian warm period ~4000 years ago, the Minoan warm period ~3000 years ago, the Roman warm period ~2000 years ago, the Medieval warm period ~1000 years ago, and the current warm period at present all roughly fall in this same 1000 year sequence of increased solar activity associated with warm periods. 

a) sunspots, b) temperature, c) CO2, d-i show the amplitudes of the strongest cycle lengths (period in years) shown in the data for sunspots, temperature, and CO2

Wavelet analysis in graph a shows the most prominent solar periods in red and graph b for temperature. The most stable period for both is at ~1024 years, shown by the horizontal region in red/yellow/light blue.

The authors find a lag of 30-40 years between changes in solar activity driving temperature, likely due to the huge thermal capacity and inertia of the oceans. Lead time shown in bottom graph of 40 years shows the temperature response following an increase or decrease of solar activity lags by about 40 years. Top graph shows "the anti-phase relation between [solar activity and temperature] keeps them stable nearly over the whole 11,000 years of the past."

The authors find temperature changes lag solar activity changes by ~40 years, which is likely due to the huge heat capacity and inertia of the oceans. Warming proponents attempt to dismiss the Sun's role in climate change by claiming 20th century solar activity peaked at around 1960 and somewhat declined from 1960 levels to the end of the 20th century (and have continued to decline in the 21st century right along with the 18+ year "pause" of global warming). 

Firstly, the assumption that solar activity peaked in 1960 and declined since is false, since it is necessary to determine the accumulated solar energy over multiple solar cycles, which is the accumulated departure from the average number of sunspots over the entire period, which I call the "sunspot integral." The sunspot integral is plotted in blue and shows remarkable correction with global temperatures plotted in red below. Correlating sunspot and temperature data with and without CO2, we find the sunspot integral explains 95% of temperature change over the past 400 years, and that CO2 had no significant influence (also here).

Source

Secondly, this paper finds strong evidence of a 30-40 year lag between solar activity and temperature response. So what happened ~40 years after the 1960 peak in sunspot activity? Why that just so happens to be when satellite measurements of global temperature peaked with the 1998 El Nino [which is also driven by solar activity], followed by the "pause" and cooling since. 

We have thus shown

• Strong correlation between solar activity and climate over the past 11,000 years of the Holocene
• Strong lack of correlation between CO2 and climate over the past 11,000 years of the Holocene
• Solar activity explains all 6 well-known warming periods that have occurred during the Holocene, including the current warm period
• The 20th century peak in sunspot activity is associated with a 40 year lag in the peak global temperature

What more proof do you need that it's the Sun!

But wait, there's more. Please see the two previous posts demonstrating that the alternate 33C greenhouse effect is due to atmospheric mass/gravity/pressure, not CO2 or water vapor, physical proof & observations that water vapor is a strong negative-feedback cooling agent, and physical proof that CO2 cannot cause any significant global warming. All of the above also strongly suggests the increase in CO2 levels is primarily due to ocean outgassing from warming oceans from the Sun, not from CO2 radiative forcing warming the oceans, and not primarily from man-made CO2 emissions.

Correlation between solar activity and the local temperature of Antarctica during the past 11,000 years

• X.H. Zhao^, , 
• X.S. Feng^, 

•

SSN [Sunspot Number] and Vostok temperature (T) had common periodicities in past 11,000 years.

•

The millennial variations of SSN and T had a strong and stable correlation.

•

The millennial variation of SSN led that of T by 30–40 years.

•

Correlations between CO₂ and T were neither strong nor stable.

---

Abstract

The solar impact on the Earth's climate change is a long topic with intense debates. Based on the reconstructed data of solar sunspot number (SSN), the local temperature in Vostok (T), and the atmospheric CO₂ concentration data of Dome Concordia, we investigate the periodicities of solar activity, the atmospheric CO₂ and local temperature in the inland Antarctica as well as their correlations during the past 11,000 years before AD 1895. We find that the variations of SSN and T have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that of T by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO₂ and T are neither strong nor stable. These results indicate that solar activity might have potential influences on the long-term change of Vostok's local climate during the past 11,000 years before modern industry.

And then they came for The Holocene: New paper suggests "removing the Holocene Epoch from the geologic timescale"

Is there any limit to the extremes some climate propagandists will go?

The Climategate team removed the warm 1940's "blip", erased the Medieval Warm Period, Hid the Decline, and tortured temperature & sea level data until it confessed, but a paper published today in Earth's Future could take the cake by suggesting removal of "the Holocene Epoch from the geologic timescale" and replacing it with the fictitious, scary-sounding "geologic" timescale "The Anthropocene."

Excerpt from "Hello Anthropocene, Goodbye Holocene": 

: "As the official timescale keepers deliberate the introduction of the Anthropocene and a Holocene-Anthropocene boundary (Anthropocene Working Group of the Subcommission on Quaternary Stratigraphy; Zalasiewicz, J., M. et al., 2010; http://goo.gl/wIm6X0 ), they should consider the alternative: Remove the Holocene Epoch from the geologic timescale. Whereas any timescale change is a contentious issue, let alone changes to an existing epoch, modern human society’s interactions with its planet and ecosystems, embodied by the Anthropocene, are sufficiently large to produce a lasting geologic marker that supports such modification. This new boundary would remain visible in the geologic record of oceans and continents (see also Corcoran et al., 2014 on plastics), meeting the stratigraphic requirements that ultimately underlie the timescale and marking a shift from the Pleistocene’s Milankovitch forcing to the Anthropocene’s human forcing. 

The Holocene is a climate-centric placeholder for change after the latest Quaternary glaciation, but does not, as defined, match the accelerated changes in land, ocean and atmosphere that mark modern times. So, I suggest that (a) we remove the Holocene altogether in favor of a (young) Anthropocene Epoch that reflects planet-wide geologic changes since c. 1900 CE, or (b) we demote the Holocene to Stage/Age status, marking the end of the Pleistocene Epoch. The latter, perhaps more palatable compromise, would recognize historical precedent and allow continued use of Holocene in the literature as a temporal (“Age”) marker. Regardless, slicing the Quaternary Period in ever thinner epochs has no geologic merit. Given the degree and impact of modern, human-induced changes on our planet, a young Pleistocene-Anthropocene boundary seems justified."

The journal titled The Holocene probably isn't going to like this idea.

The fact is the tiny 0.7C recovery since the end of the Little Ice Age in ~1850, which is coincidentally when the global temperature record begins, could easily be natural and 95% explained by solar activity and ocean oscillations, and is not unprecedented or unusual within the past ~10,000 years of the Holocene Epoch. Thousands of paleoclimate papers show the Medieval, Roman, Egyptian, Minoan, and multiple other unnamed warm periods within the Holocene were warmer than the present. In addition, the Pacific Ocean has been significantly warmer than the present throughout vast majority of the Holocene. 

Further, during the last interglacial ~120,000 years ago, Greenland was up to 8C warmer than the current interglacial warm period, and sea levels were up to 29 feet higher. Therefore, there is no evidence that warmth during the current interglacial warm period is unprecedented, unusual, or unnatural.

Therefore, there is no valid reason whatsoever to remove the Holocene Epoch "blip" from the geological timescale, despite how convenient it would be for the climate propagandists. Kinda bad timing too promoting the silly Anthropocene/Mannocene notion that man-made CO2 controls the climate given the 50+ excuses for the absence of global warming for the past 18-26 years despite a steady rise in CO2.

GISP2 Greenland ice core data in blue, the tiny 0.7C "Anthropocene" warming of HADCRU sea surface temperatures to present-day shown in red spliced at end

Above GISP2 Greenland ice core data with labeled warm periods

Present Greenland temperatures haves been exceeded many times over past 4000 yrs Full paper

Temperatures during the last interglacial period ~120,000 years ago [and several other interglacials] were higher than during the present interglacial period.

Holocene Epoch shown at lower right, as well as the lack of correlation on geologic timescales between CO2 and temperature.

On geologic timescales, we are still in an ice age, because there are ice sheets present at both poles

New paper finds Chilean ocean temperatures were consistently warmer than present-day over most of past 12,000 years

A paper published today in Quaternary Research finds 6 more non-hockey-sticks in reconstructed sea surface temperatures [SSTs] over the past 12,000 years from 6 different latitudes along the southern coast of Chile. The reconstructed temperatures show most of the Holocene [past ~11,000 years] had consistently warmer sea surface temperatures than present-day temperatures. According to the authors, 

"The Holocene records show consistently warmer than present-day Sea Surface Temperatures except for [~ 600 years during the Little Ice Age]."

The paper joins hundreds of published non-hockey-stick temperature reconstructions worldwide demonstrating the Medieval, Roman, Egyptian, and Minoan Warm Periods, and Holocene Climate Optimum were all naturally warmer than present-day temperatures. 

Horizontal axis is thousands of years before the present. SST = Sea Surface Temperatures. Present-day SSTs indicated with arrows along the vertical axis

Add caption

LIA = Little Ice Age, MCA = Medieval Warm Period. Note top graph appears to be based upon one of Mann's bogus temperature reconstructions. Remaining graphs show SST reconstructions along southern coast of Chile. 

Holocene sea-surface temperature variability in the Chilean fjord region

• Magaly Caniupán^a, , , 
• Frank Lamy^a, 
• Carina B. Lange^b, 
• Jérôme Kaiser^c, 
• Rolf Kilian^d, 
• Helge W. Arz^c,
• Tania León^b, 
• Gesine Mollenhauer^a, 
• Susana Sandoval^b, 
• Ricardo De Pol-Holz^e, 
• Silvio Pantoja^b, 
• Julia Wellner^f, 
• Ralf Tiedemann^a
• • 
    

Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day Sea Surface Temperatures except for the past ~ 0.6 cal ka BP [Little Ice Age]. However, they do not exhibit an early Holocene temperature optimum as registered further north off Chile and in Antarctica. This may have resulted from a combination of factors including decreased inflow of warmer open marine waters due to lower sea-level stands, enhanced advection of colder and fresher inner fjord waters, and stronger westerly winds. During the mid-Holocene, pronounced short-term variations of up to 2.5°C and a cooling centered at ~ 5 cal ka BP, which coincides with the first Neoglacial glacier advance in the Southern Andes, are recorded. The latest Holocene is characterized by two pronounced cold events centered at ~ 0.6 and 0.25 cal ka BP, i.e., during the Little Ice Age. These cold events have lower amplitudes in the offshore records, suggesting an amplification of the SST signal in the inner fjords.

New paper predicts future warming is likely to reduce the number of floods

A new paper published in Global and Planetary Change finds on the basis of paleoclimate data over the past 6,000 years that "future warming is likely to reduce the number of floods."

According to the paper, "although most climate models agree on a general increase in future precipitation in the Northern Hemisphere due to higher temperatures, no consensus has yet been reached on how this warming will perturb flooding rates." The authors find however, "Despite an anticipated increase in Pw [winter precipitation], the paleodata, nevertheless, suggest that we are likely to witness a decrease in future floods 50–100 years from now because the accompanying warming will cancel that net effect of a wetter regime." The paper adds to many other peer-reviewed papers finding flooding is more common during cold periods, such as the Little Ice Age [LIA] and Dark Ages Cold Period [DACP].

Horizontal axis is years before the present. Floods were less common during the Holocene Climate Optimum ~6,000 years ago, Minoan Warm Period ~3,000 years ago, Roman Warm Period ~2,000 years ago, as well as over the past two centuries. Flooding was more common during the Little Ice Age and Dark Ages Cold Period.

Scandinavian floods: From past observations to future trends

• Eivind N. Støren^a, b, , , 
• Øyvind Paasche

Highlights

•

Winter precipitation and floods are linked on longer time scales.

•

Wetter winter regimes in mountainous areas produce more floods.

•

Future warming is likely to reduce the number of floods.

---

Abstract

Although most climate models agree on a general increase in future precipitation in the Northern Hemisphere due to higher temperatures, no consensus has yet been reached on how this warming will perturb flooding rates. Here we examine the potential co-variability between winter precipitation (Pw) and floods on millennial time scales. This is accomplished by analyzing reconstructed Pw from five records in Scandinavia, which is, compared to data from two high-resolution flood records from southern Norway. These Holocene records reveal a positive correlation (R² = 0.41, p > 0.01) between the number of floods and Pw [winter precipitation] on centennial time scales over the last 6000 years. Future projections for Pw over central Scandinavia for the next 100 years suggest a continued increase in Pw that approximates maximum Holocene precipitation values. Despite an anticipated increase in Pw [winter precipitation], the paleodata, nevertheless, suggest that we are likely to witness a decrease in future floods 50–100 years from now because the accompanying warming will cancel that net effect of a wetter regime.

How to lie with climate statistics & probability, version 10¹³

A paper published today in the Journal of Geophysical Research claims that the probability of the streak of contiguous US average monthly temperatures from June 2011 - June 2012 "occurring randomly was quoted as (1/3)^13, or about one in 1.6 million." 

This is odd, given that more than 1,200 peer-reviewed, published non-hockey-sticks demonstrate the Medieval Warm Period [worldwide including North America] was as warm or warmer than the present. There is also ice core data from the Arctic and Antarctic, and hundreds of other proxy studies indicating the Roman, Minoan, Egyptian, Holocene Climate Optimum, and many other unnamed warming periods were warmer than the present. The last interglacial was ~8C warmer than the present, as were almost all of the other interglacials over the past 5.2 million years. 

Maybe it's just me looking at those stupid denier lines, but seems to me the chances that such a "temperature streak" could occur naturally in the US [only 2% of the planet!] are to an approximation about one million in one million. 

The background on how skeptics view those stupid global warming denier lines:

UPDATE: Sunshine Hours analyzed the US temperature record and found another similar "temperature streak" in 1933/1934, and that's after all of the fraudulent up-justing of the US temperature records:

The Hockey Schtick blog brought a recent paper to my attention.

The abstract says:

“A recent observation in NOAA’s National Climatic Data Center’s monthly assessment of the state of the climate was that contiguous US average monthly temperatures were in the top third of monthly ranked historical temperatures for thirteen straight months from June 2011 — June 2012. The chance of such a streak occurring randomly was quoted as (1/3)¹³, or about one in 1.6 million.”

I’m not going to discuss the “chances”. But I am going to simply note the following.

The NOAA ranks months temperature and precipitation based on the number of months from 1895. So 2012 was the 118th year. If a month is ranked 118 (as of 2012) then it was the warmest month from 1895 to 2012.

Using the same 12 month June to June time frame and using data from October 2012 ( before NOAA’s recent update) it took me about 10 minutes to find out a similar streak.

From June 1933 to to June 1934 8 months were ranked 100 and above. 2 of them were ranked 118.

From June 2011 to June 2012 8 months were ranked 100 and above. 1 of them was ranked 118.

year	Month	Rank
1933	6	118
1933	7	104
1933	9	116
1933	12	115
1934	1	114
1934	4	107
1934	5	118
1934	6	108

year	Month	Rank
2011	7	114
2011	8	117
2012	1	115
2012	2	104
2012	3	118
2012	4	116
2012	5	117
2012	6	107

What are the odds of that occurring 80 years apart!

Warm Streaks in the US Temperature Record: What are the Chances?

Peter F. Craigmile et al

A recent observation in NOAA's National Climatic Data Center's monthly assessment of the state of the climate was that contiguous US average monthly temperatures were in the top third of monthly ranked historical temperatures for thirteen straight months from June 2011 — June 2012. The chance of such a streak occurring randomly was quoted as (1/3)13, or about one in 1.6 million. The streak continued for three more months before the October 2012 value dropped below the upper tercile. The climate system displays a degree of persistence that increases this probability, relative to the assumption of independence. This paper puts forth different statistical techniques that more accurately quantify the probability of this and other such streaks. We consider how much more likely streaks are when an underlying warming trend is accounted for in the record, the chance of streaks occurring anywhere in the record, and the distribution of the record's longest streak.

CERN scientist says another Maunder Minimum in solar activity could occur by 2015

Dr. Jasper Kirkby, head of the CLOUD Experiment at CERN in Geneva notes in the video lecture below that if one extrapolates the current lull in solar activity, an extended period of no sunspots similar to the Maunder Minimum could occur by 2015. The Maunder Minimum was responsible for the Little Ice Age and lasted for 70 years. 

Above slide from Dr. Kirby's lecture around 9:50 mark shows reconstructed solar activity over the past 6,000 years. Dr. Kirby's preceding slide in the lecture below shows extrapolated solar activity could reach levels of the Little Ice Age [LIA] within only 2 more years. Also shown are the peaks in solar activity corresponding to the Medieval Warm Period ~1000 years ago, the Roman Warm Period ~2000 years ago, the Egyptian and Minoan Wam Periods ~3000 and 4000 years ago, and the Current Warm Period of the 20th century.

 

Same reconstructed solar activity cited above by Dr. Kirby: Vonmoos et al 2006 



Jasper Kirkby Head of the CLOUD Experiment - CERN, Geneva. This lecture is part of SFU's 2011 global warming seminar series "Global Warming: A Science Perspective".

Read more at http://www.liveleak.com/view?i=414_1315052227#454TUBbgTXPOkpAt.99

H/T Joe Bastardi

New paper finds climate models are unable to reproduce warming during the Holocene Climate Optimum

A new paper published in Climate of the Past finds that climate models are unable to reproduce the warming in East Asia during the Holocene Climate Optimum. According to the authors, "Much effort has been devoted to reconstructing the mid-Holocene climate over East Asia using a variety of proxy data, suggesting that China experienced warmer and wetter than present climate conditions as a whole during that time," however climate model "results are contrary to the warming reconstructed from multiple proxy data for the mid-Holocene." The paper adds to many other peer-reviewed publications demonstrating that climate models are unable to reproduce the Holocene Climate Optimum, Egyptian, Minoan, Roman, and Medieval Warming Periods, all of which were warmer than the present. Climate models are unable to reproduce the known climate of the past, much less the future. 

Clim. Past, 9, 2153-2171, 2013 www.clim-past.net/9/2153/2013/ doi:10.5194/cp-9-2153-2013 Mid-Holocene ocean and vegetation feedbacks over East Asia

Z. Tian^1,2 and D. Jiang^1,3,4
1Nansen–Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
²University of Chinese Academy of Sciences, Beijing, China
³Key Laboratory of Regional Climate–Environment Research for Temperate East Asia, Chinese Academy of Sciences, Beijing, China
⁴Climate Change Research Center, Chinese Academy of Sciences, Beijing, China
Abstract. Mid-Holocene ocean and vegetation feedbacks over East Asia are investigated by a set of numerical experiments performed with the version 4 of the Community Climate System Model (CCSM4). With reference to the pre-industrial period, most of the mid-Holocene annual and seasonal surface-air temperature and precipitation changes are found to result from a direct response of the atmosphere to insolation forcing, while dynamic ocean and vegetation modulate regional climate of East Asia to some extent. Because of its thermal inertia, the dynamic ocean induced an additional warming of 0.2 K for the annual mean, 0.5 K in winter (December–February), 0.0003 K in summer (June–August), and 1.0 K in autumn (September–November), but a cooling of 0.6 K in spring (March–May) averaged over China, and it counteracted (amplified) the direct effect of insolation forcing for the annual mean and in winter and autumn (spring) for that period. The dynamic vegetation had an area-average impact of no more than 0.4 K on the mid-Holocene annual and seasonal temperatures over China, with an average cooling of 0.2 K for the annual mean. On the other hand, ocean feedback induced a small increase of precipitation in winter (0.04 mm day⁻¹) and autumn (0.05 mm day⁻¹), but a reduction for the annual mean (0.14 mm day⁻¹) and in spring (0.29 mm day⁻¹) and summer (0.34 mm day⁻¹) over China, while it also suppressed the East Asian summer monsoon rainfall. The effect of dynamic vegetation on the mid-Holocene annual and seasonal precipitation was comparatively small, ranging from −0.03 mm day⁻¹ to 0.06 mm day⁻¹ averaged over China. In comparison, the CCSM4 simulated annual and winter cooling over China agrees with simulations within the Paleoclimate Modeling Intercomparison Project (PMIP), but the results are contrary to the warming reconstructed from multiple proxy data for the mid-Holocene. Ocean feedback narrows this model–data mismatch, whereas vegetation feedback plays an opposite role but with a level of uncertainty.

New paper finds another non-hockey-stick in China

A new paper published in Quaternary Science Reviews reconstructs the mean annual temperature in the Pearl River Basin, China over the past ~6,300 years and finds another non-hockey-stick with the modern mean annual temperature of ~15.4C exceeded many times in the past including during the Medieval, Roman, Minoan, and Egyptian Warming Periods, and by the Holocene Climate Optimum. 

Horizontal axis is years before the present. Modern mean annual temperature is ~15.4 C.

A new regional, mid-Holocene palaeoprecipitation signal of the Asian Summer Monsoon

• D. Strong^a, b, 
• R. Flecker^a, , , 
• P.J. Valdes^a, 
• I.P. Wilkinson^c, 
• J.G. Rees^c, 
• K. Michaelides^a, 
• Y.Q. Zong^d,
• J.M. Lloyd^e, 
• F.L. Yu^f, 
• R.D. Pancost^b

• ^a School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
• ^b Organic Geochemistry Unit, The Cabot Institute, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK
• ^c British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK
• ^d Department of Earth Sciences, University of Hong Kong, James Lee Sciences Building, Pokfulam Road, Hong Kong, China
• ^e Department of Geography, University of Durham, South Road, Durham DH1 3LE, UK
• ^f Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Avenue, Block N2-01a-15, 639798, Singapore

---

Highlights

•

The Dongge speleothem δ¹⁸O record mirrors the Pearl River Estuary BIT record.

•

This suggests both are driven by regional precipitation (Asian Summer Monsoon).

•

Leaf wax δ¹³C values reflect the initiation of anthropogenic cultivation ∼2 ka.

•

Scale-equivalent comparison with climate model-data is possible for the first time.

---

Abstract

The Dongge Cave speleothem δ¹⁸O record, which lies in the Pearl River basin (China), has been interpreted as recording a regional decline in Asian Summer Monsoon precipitation over the last 6.5 ka. The same overall trend is seen in the bulk sedimentary organic δ¹³C_org record from a core in the Pearl River Estuary. However, the two records differ in detail and the regional nature of the Dongge palaeoprecipitation signal has therefore been questioned. Our study re-evaluates both records by constructing, for the same estuarine core, biomarker and compound-specific δ¹³C records, which have better constrained terrestrial and marine end members than δ¹³C_org, providing additional insights into the evolution of the Asian Summer Monsoon.

The Branched Isoprenoidal Tetraether (BIT) index reflects the ratio of soil versus marine organic matter. The BIT record from the estuarine core co-varies with the Dongge Cave δ¹⁸O record suggesting the two share a common control which is likely to be driven by regional climate. By contrast, the sterols, n-alcohols and n-fatty acid ratios show the same overall trend as Dongge, but parallel the δ¹³C_org record's variability between 6.5 and 2 ka indicating a partial decoupling between soil and land-plant organic matter fluxes in the Pearl River Basin. There is clear divergence between the biomarker and ¹³C_org records from 2 ka to present. Analysis of the leaf wax δ¹³C suggests that this results from an abrupt change in vegetation probably resulting from local, anthropogenic cultivation two thousand years ago.

The basin scale of these estuarine records equates to up to 15 grid cells in typical Earth System Models used for simulating global climate. This permits comparison of Palaeoclimate Model Intercomparison Project simulations of the mid-Holocene with spatially equivalent data relating to the Summer Asian Monsoon, for the first time.