Wednesday, 9 October 2013

Rising Sea Levels

Rising Sea Levels?

by Anthony Cox

Damon Cronshaw’s article about rising sea levels drowning the CBD of Newcastle had its amusing side with a shark meandering up King Street. However, given the chronic failure of predictions by the Intergovernmental Panel for Climate Change [IPCC] there is probably an equal chance of that shark getting a speeding ticket as there is King Street having enough water covering it to allow the shark to swim up it.

The IPCC has just released its fifth report, AR5. Chapter 13 of AR5 deals with sea level rise. Chapter 13 predicts a sea level rise of between 0.26 and 0.97 of a metre by the year 2100. So even if the worst prediction by the IPCC of 0.97 metres comes true the shark will lose a lot of bark from the road surface as it swims up King Street.

Sea rise comes about from 3 different causes.

Firstly there is steric sea rise which is based on a warming sea and thermal expansion of the water. Chapter 13 of AR5 is very confident there is thermal expansion. However it is indisputable that the sea surface has COOLED since 2003.

And the ocean down to 700 metres has warmed less than 0.01C since 2003 which is statistically insignificant from zero.

The IPCC claims the missing heat is at the ocean bottom but has yet to explain how the heat can go past the top of the ocean without leaving any trace of warming.

The second way the sea level can rise is through eustatic rise. Eustatic rise is by extra water coming into the ocean. The main source of fresh water into the ocean is from the world’s biggest sources of freshwater, Greenland and the Antarctic.

New research from 2012 shows both the Greenland and Antarctic ice sheets have decreases in ice in some regions matched by ice increase in other parts.

So it appears the sea level rise can’t be from either warming or more water.

The final way sea level can rise is through isostatic processes or movement in the land itself. But this process has nothing to do with climate.

Given this can we be sure sea level is rising. Two definitive studies of sea level were done in 2011. The first by Houston and Dean looked at global sea level and concluded the rate of sea level rise was decreasing not increasing as Chapter 13 of AR5 predicts.

The second study was by Australian researcher Dr Phil Watson from the NSW Department of the Environment. Dr Watson also concluded that sea level rate of increase was declining and there was no sign of the acceleration in sea level rise predicted by the IPCC.

Newcastle measurement of sea level rise is by the international group Permanent Service for Mean Sea Level [PSMSL]. PSMSL has four sea level gauges at Newcastle.

The gauges have been in use for varying periods of time. 
  • Gauge 1 shows an abrupt increase in 1948, probably due to isostasy and no increase from 1950 to 1960.
  • Gauge 2 shows a decrease from 1972 to 1983.
  • Gauge 3 shows a decrease from 1975 to 1990.
  • Gauge 4 shows a decrease from 2000.

In other words the only way our shark is going up King Street is as fish and chips.

Climate Models may be detrimental - IPCC be warned.

The American Meteorological Society in their Journal of Climate 26 Issue 12 have published a paper

Evaluation of Temperature and Precipitation Trends and Long-Term Persistence in CMIP5 Twentieth-Century Climate Simulations

The authors have analyzed twentieth-century temperature and precipitation trends and long-term persistence from 19 climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). This study is focused on continental areas (60°S–60°N) during 1930–2004 to ensure higher reliability in the observations. A nonparametric trend detection method is employed, and long-term persistence is quantified using the Hurst coefficient, taken from the hydrology literature.
From CO2 Science: (link)

What was learned

Although some things were done well by the participating models, others were not. Kumar et al. report, for example, that "the models capture the long-term persistence in temperature reasonably well," but they say that "the models have limited capability to capture the long-term persistence in precipitation." They also state that "most climate models underestimate the spatial variability in temperature trends," and they say there were "large uncertainties in the simulation of regional-/local-scale temperature and precipitation trends." In addition, they report that "Sakaguchi et al. (2012a,b) have evaluated the simulation skill for temperature trends from selected CMIP3 and CMIP5 climate models," finding "limited skill in the simulation of temperature trends at regional scales in these climate models."

Finally, "from a regional natural resource planning perspective," the four scientists write that the multimodel-ensemble averages provide what they kindly call "conservative value for planning or design." As an example, they note that "the India and West Africa regions are drying much faster (-20 mm/decade) in the observations than simulations by the multimodel-ensemble average (-5 mm/decade)," while similarly noting that "north-central Asia is warming twice as fast as the global-average warming," which is something "not found in the multimodel-ensemble average."

What it means

Clearly, the best climate models of the present day are still not up to doing what we really need them to do to be of much service. In fact, they could potentially be leading us in a direction we may soon find to actually be detrimental to the well-being of the biosphere, including ourselves. (emphasis added)

Read More at CO2 Science