Comments on: Indonesia’s Climate Follows the Sun

By: Tim Curtin

Tim Curtin — Fri, 28 Nov 2008 04:32:42 +0000

Luke: you need to read more of Long, eg 1991, and here, in Plant, Cell, and Environment (2006): Can improvement in photosynthesis increase crop yields?
STEPHEN P. LONG , XIN-GUANG ZHU , SHAWNA L. NAIDU & DONALD R. ORT
ABSTRACT
The yield potential (Yp) of a grain crop is the seed mass per
unit ground area obtained under optimum growing conditions
without weeds, pests and diseases. It is determined by
the product of the available light energy and by the genetically
determined properties: efficiency of light capture (ei), the efficiency of conversion of the intercepted light into biomass (ec) and the proportion of biomass partitioned into
grain (h). Plant breeding brings (greek n) and ei
close to their theoretical maxima, leaving ec, primarily determined by
photosynthesis, as the only remaining major prospect for
improving Yp. Leaf photosynthetic rate, however, is poorly
correlated with yield when different genotypes of a crop
species are compared. This led to the viewpoint that
improvement of leaf photosynthesis has little value for
improving Yp. By contrast, the many recent experiments
that compare the growth of a genotype in current and
future projected elevated [CO2] environments show that
increase in leaf photosynthesis is closely associated with
similar increases in yield. Are there opportunities to
achieve similar increases by genetic manipulation? Six
potential routes of increasing ec by improving photosynthetic
efficiency were explored, ranging from altered canopy
architecture to improved regeneration of the acceptor
molecule for CO2. Collectively, these changes could
improve ec and, therefore, Yp, by c. 50%. Because some
changes could be achieved by transgenic technology, the
time of the development of commercial cultivars could be
considerably less than by conventional breeding and potentially,
within 10–15 years.

By: Luke

Luke — Thu, 27 Nov 2008 12:19:45 +0000

400? coz that’s what data Franks has … expediency

no it doesn’t explain the modern era at all – - just the interdecadal variations.

Looks to me like a global warming signal coming over the top of an interdecadal oscillation

Your job still awaits you

Tim Tim Tim – fancy quoting Long

Science 30 June 2006:
Vol. 312. no. 5782, pp. 1918 – 1921
DOI: 10.1126/science.1114722

Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations
Stephen P. Long,1,2,3* Elizabeth A. Ainsworth,4,1,3 Andrew D. B. Leakey,3,1 Josef Nösberger,5 Donald R. Ort4,1,2,3

Model projections suggest that although increased temperature and decreased soil moisture will act to reduce global crop yields by 2050, the direct fertilization effect of rising carbon dioxide concentration ([CO2]) will offset these losses. The CO2 fertilization factors used in models to project future yields were derived from enclosure studies conducted approximately 20 years ago. Free-air concentration enrichment (FACE) technology has now facilitated large-scale trials of the major grain crops at elevated [CO2] under fully open-air field conditions.

In those trials, elevated [CO2] enhanced yield by ~50% less than in enclosure studies. This casts serious doubt on projections that rising [CO2] will fully offset losses due to climate change.

By: cohenite

cohenite — Thu, 27 Nov 2008 11:54:35 +0000

luke; pdo and temp over 400 years; why 400? Anyhow, FIG 10 from this source is interesting;

http://www.ac.wwu.edu/~dbunny/research/global/glacialfluc.pdf

Which explains the modern era;

http://climate-skeptic.typepad.com/photos/uncategorized/2008/09/18/pdo.gif

By: Tim Curtin

Tim Curtin — Thu, 27 Nov 2008 10:24:02 +0000

Luke: Try Norby & Luo New Phytologist 2004, 162: 281-293; Long et al., in Plant , Cell, and Environment 2006.

By: Luke

Luke — Thu, 27 Nov 2008 07:56:55 +0000

Come on Tim – your CO2 fertilisation stuff is so trite. You’d be flat out detecting current levels in field trials. Look at the FACE experiments – incredibly variable results. And you have to have the rainfall to go with the CO2. In woodlands – seems that the acacias take over. Seems to affect the C/N ratios. And woody plants in general overrun grasses – and yes I await you obvious retort but CO2 increases frost sensitivity. One unusual cold snap and zappo !

How about some full disclosure here and not the usual sceptic simplistic nonsense.

By: Tim Curtin

Tim Curtin — Thu, 27 Nov 2008 00:12:19 +0000

To our resident expert on Miskolczi, SJT, who is evidently unable to answer the following questions I put to him nearly 2 days ago: “what is your opinion on what would be the optimal level of [CO2]? Do you agree with Hansen (350 ppm)? or those who consider zero emissions best, leading to long term decreasing [CO2] for so long as uptakes continue at the present nearly 6 GtC p.a. which would reduce us to the 1750 level perhaps as early as 2070 if not before? If uptakes drop in line with reducing emissions, what then for CO2 fertilisation? Will wheat etc yields remain as they are, or fall? Was 1750’s 280 ppm ideal? Would it feed 6.5+ billion?

By: SJT

SJT — Wed, 26 Nov 2008 08:23:51 +0000

This is strange; Miskolczi explains how optical density is regulated by water vapor

Miskolczi doesn’t explain it at al. He claims it, but he offers no explanation.

By: Luke

Luke — Tue, 25 Nov 2008 23:31:13 +0000

It’s almost ironic that Jen would have posted on Indonesia just when this IOD paper has come out. And speaking of Indonesian SSTs it says:

“Strengthened upwelling in the eastern IOD sector implies
that there has been an intensification of the southeasterly trade
winds along the coast of Sumatra, and/or shoaling of the
thermocline in the eastern IOD sector2,16. Historical ship-based
measurements support a twentieth-century intensification of the
southeasterly trade winds offshore of Sumatra (Fig. 3c). This is
consistent with theories that preferential greenhouse warming of
landmasses will strengthen alongshore winds26. This process has
been linked to intensified coastal upwelling in other locations27,
and may account for the enhanced upwelling in the eastern IOD
region. The influence of twentieth-century warming on long-term
changes in the Walker circulation over the tropical Pacific11 may
have also enhanced eastern IOD upwelling. Twentieth-century
weakening of the Walker overturning cell has been accompanied
by an eastward displacement of convection over Indonesia and
shoaling of the thermocline in the Indo-Pacific Warm Pool11,25.
Both processes are consistent with an intensification of the IOD
via the eastern Indian Ocean upwelling region, with reduced
convection favouring the development of anomalous surface
easterly winds and shoaling of the thermocline assisting upwelling
of cooler waters.”

Wow !

By: Luke

Luke — Tue, 25 Nov 2008 23:18:57 +0000

And Cohers – just when you think more evidence couldn’t wash in – our old friend the IOD – latest Nature Geoscience – IOD has also changed over the 20th century … bit of a pattern developing …
http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo357.html

Add that to http://www.nature.com/news/2008/081106/full/news.2008.1213.html

Poing !

Dare one says there seems to be major changes across the whole southern hemisphere as extra “energy” redistributes.

By: Luke

Luke — Tue, 25 Nov 2008 23:02:31 +0000

Cohers – SOI been trending down for 30 years and way different to anything in 100 years. Why do you think climatologists are picking up on it. Why do you think they’re wondering what such a change means for ENSO indices and seasonal forecasting.

PDO and SOI aren’t well correlated in first half of the 20th century. So I’m suggesting you’re just grabbing at one cycle.

And Scott and Power have teased us – see their title – Walker circulation has changed but is El Nino still the same. Very interesting.

Now add on the STR change over the century.

The observed changes in SAM backed up by modelling by a number of groups.

If by now you’re not getting any gnawing doubts there’s something wrong…. well ….

Anyway where’s your 400 years of global temperature versus 400 years of PDO. Boing – ping – was that a spring gasket blowing …?