October 28, 2017

The downfall of the proxies

The article below is more significant than its authors appear to realize.  It casts all proxy measurements of temperature into doubt -- and paleoclimate studies all rely on proxies. For most of the world, thermometer measurements of temperature go back only a couple of hundred years, if that.  So paleoclimatologists DEDUCE temperatures from what they see in tree rings, sedimentary sea-life, ice-cores etc.  Such things are proxies for actual temperature measurements.

And it has just been revealed that a widely used and completely accepted proxy appears to be severely inaccurate.

There have long been protests at the uncritical acceptance of proxies. Perhaps the most vivid example of proxy inaccuracy was "Mike's Nature trick", where Michael Mann abandoned mention of 20th century tree-ring proxies when he found that they showed a 20th century temperature DECLINE.  Where it could be examined, there was a wide divergence between tree ring proxies and actual temperatures as measured by thermometers.  Tree rings have in other words been shown to be invalid as a measure of temperature.  Any work using them is built on sand.

And Dr Zbigniew Jaworowski's criticisms of the assumed reliability of ice core measurements of gases such as CO2 have often been mentioned. And he studied ice cores for over 30 years.

And the measurements of actual CO2 levels collated by Ernst Beck from 1812 on diverge strongly from proxy measurements.

So doubts about proxies have been voiced before but have been ignored by Warmists.  The latest study, however should be harder to ignore, given its importance to paleoclimate work.  "Paleoclimatology is bunk" would seem to be a reasonable conclusion given what we now know. Its measurements require a large element of faith and that faith has now been shown to be misplaced


Climate change might be even worse than we think, according to a new study that is challenging the way we measure ocean temperatures.

Scientists suggest that the method used to understand sea temperatures in the past is based on a mistake, meaning our understanding of climate change may be flawed.

The findings indicate that oceans in the past were much colder than thought, meaning that temperatures may be increasing quicker now than realised.

For over 50 years, scientists based their estimates on what they learned from foraminifera - fossils of tiny marine organisms found in sediment cores taken from the ocean floor.

Foraminifera form shells called tests, in which the content of a form of oxygen, called oxygen-18, depends on the temperature of the water.

So changes in the ocean's temperature over time were calculated on the basis of the oxygen-18 content of the fossil foraminifera tests found in sediment.

According to these measurements, the ocean's temperature has fallen by 15°C over the past 100 million years.

But these estimates were based on the principle that the oxygen-18 content of the foraminifera tests remained constant while the fossils were in the sediment.

To test whether oxygen-18 levels changed, the researchers exposed foraminifera to high temperatures in artificial sea water that contained only oxygen-18.

An instrument called NanoSIMS was then used to analyse the chemical content of the fossils.

Results show that the level of oxygen-18 changed without leaving a visible trace.

According to the methodology widely used by the scientific community, the temperature of the polar oceans 100 million years ago were around 15°C higher than current readings.

But in a new study, researchers from the French National Center for Scientific Research (CNRS) are challenging this method.

Instead, they suggest that ocean temperatures may in fact have remained relatively stable throughout this period, which raises serious concerns about current levels of climate change.

Dr Anders Meibom, one of the researchers who worked on the study, said: 'If we are right, our study challenges decades of paleoclimate research.'

'Oceans cover 70 per cent of our planet. They play a key role in the earth's climate.

'Knowing the extent to which their temperatures have varied over geological time is crucial if we are to gain a fuller understanding of how they behave and to predict the consequences of current climate change more accurately.'

For over 50 years, scientists have based their estimates on what they learned from foraminifera - fossils of tiny marine organisms found in sediment cores taken from the ocean floor.

Foraminifera form shells called tests, in which the content of a form of oxygen, called oxygen-18, depends on the temperature of the water in which they live.

So changes in the ocean's temperature over time were calculated on the basis of the oxygen-18 content of the fossil foraminifera tests found in the sediment.

According to these measurements, the ocean's temperature has fallen by 15°C over the past 100 million years.

But these estimates were based on the principle that the oxygen-18 content of the foraminifera tests remained constant while the fossils were in the sediment.

To test whether oxygen-18 levels changed, the researchers exposed foraminifera to high temperatures in artificial sea water that contained only oxygen-18.

An instrument called NanoSIMS was then used to analyse the chemical content of the fossils.

Results show that the level of oxygen-18 present changed without leaving a visible trace.

Dr Sylvain Bernard, lead author of the study, said: 'What appeared to be perfectly preserved fossils are in fact not.

'This means that the paleotemperature estimates made up to now are incorrect.'

Rather than showing a gradual decline in temperature over the past 100 million years, the researchers suggest that the foraminifera had changed their oxygen-18 levels simply to equilibrate with the surrounding water.

The findings indicate that temperature in the oceans have been overestimated.

In terms of next steps, Dr Meibom added: 'To revisit the ocean's paleotemperatures now, we need to carefully quantify this re-equilibration, which has been overlooked for too long.

'For that, we have to work on other types of marine organisms so that we clearly understand what took place in the sediment over geological time.'

SOURCE




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