but is it science · Climate Change · Environment · science and philosophy

AGW Claims vs Truth – Claim 8: The world is in danger of catastrophic consequences – sea level rise, polar ice and glaciers melting, growing deserts, worse storms, droughts and floods

Claim 8: The world is in danger of catastrophic consequences of global warming such as sea level rise, polar ice and glaciers melting, growing deserts, worse storms, droughts and floods.

 Truth: a.) Sea levels have been rising along with warming since the Little Ice Age at an average rate of 7 inches per century due to glacier melting and expansion of seawater with warming. This rate has not changed significantly in recent times. To claim that sea levels have risen, the IPCC used a tide gauge in Hong Kong that showed tide levels rising, not because of sea level rising, but because the land is sinking (subsiding).  Those islands that were supposedly in danger of being swamped have had almost no net sea level rise in all the years since the early predictions. Globally, some land has been lost due to sea level rise and subsidence, but more land has been gained by other forces.

Sea Level Rise since the Little Ice Age
Sea Level Rise since the Little Ice Age

Source: “Environmental Effects of Increased Atmospheric Carbon Dioxide”[1]  Note that it is not correlated to fossil fuel consumption

b.) Polar ice caps have shrunk and grown in recent years but overall they have remained relatively unchanged since preindustrial times. The media hype is about a theory that the Larsen Ice Shelf (in the more northerly Western Antarctica peninsula) might break away from Antarctica, causing rapid sea level rise of 5 meters (16.4 ft.). Although a part broke away in 1995, most experts say rapid collapse will not happen and any collapse and sea level rise would occur over centuries[2]. Both sea ice and ice cover have grown even more in other, more southerly locations on the continent. This year northern polar sea ice was thicker than usual so that there was some concern that the polar bears might have a harder time finding seals to eat. By the way, polar bear populations have been increasing in recent years.

c.) Glaciers have been receding since the Little Ice Age at a relatively steady pace that, along with water expansion with warming, accounts for much of the sea level rise. Melting of floating sea ice doesn’t cause a rising sea level. It is already displacing its weight in saltwater. Ice expands as it freezes, so that melt water shrinks as it melts, resulting in the release of the same weight of water as was originally displaced. Only land-based glaciers will have any effect on sea level. While most glaciers are receding, there are some that are actually growing.

CO2 Increase since 1950 does not track Glacier Shortening
CO2 Increase since 1950 does not track Glacier Shortening

Source: “Environmental Effects of Increased Atmospheric Carbon Dioxide”[3]

d.) Droughts have not increased in recent times. Some years are worse than others, but the overall picture has not changed.

Global drought monitoring - nature
Global drought monitoring

Global Drought: Fraction of the global land in D0 (abnormally dry), D1 (moderate), D2 (severe), D3 (extreme), and D4 (exceptional) drought condition (Data: Standardized Precipitation Index data derived from MERRA-Land)[4]

e.) Deserts are generally a result of geographic barriers and over grazing. Most of the Sahara Desert was once a grassy plain where livestock were grazed. It is a naturally dry area due to mountains to the west that block much of the moisture from the Atlantic Ocean. Overgrazing and loss of denuded top soil by winds had contributed to its expansion long before the industrial age. In most areas of the world, there has been no marked increase in the rate of desertification in recent times. Instead, deserts are greening as a result of higher CO2 levels that increase growth rates and make plants more tolerant of dry conditions by reducing the leaf pores. See previous post AGW Claims 2b The Benefits of Carbon Dioxide, answer c.

f.) Storms have not gotten worse. The dollar damages in some areas have increased due to increased urbanization, but not the severity of the storms themselves. The number of tornados has actually declined in the United States and their severity has not increased. The same is true of hurricanes and in recent years few have made landfall in the United States.

US Annual Severe Tornados

[1] Review Article: “Environmental effects of increased atmospheric carbon dioxide,” Willie Soon, Sallie L. Baliunas, Arthur B. Robinson, Zachary W. Robinson, Climate Res. 13, 149-164, (1999)

[2] Quote: “More realistically, ice-shelf deterioration is likely to be a rather slow process, and even for a major and sustained warming trend ice-sheet collapse would take several hundred years, with most of the associated rise in sea level occurring during the final century.” From Nature 277, 355 – 358 (01 February 1979); doi:10.1038/277355a0 “Effect of climatic warming on the West Antarctic ice sheet Robert H. Thomas1.), Timothy J. O. Sanderson2.) & Keith E. Rose3.) from 1.) Institute for Quaternary Studies, University of Maine at Orono, Orono, Maine 04469, 2.) British Antarctic Survey, Cambridge, UK, 3.)Scott Polar Research Institute, Cambridge, UK Present address: Department of Geophysics, Royal School of Mines, Imperial College, London SW7, UK http://www.nature.com/nature/journal/v277/n5695/abs/277355a0.html

[3] Reference: ”Extracting a Climate Signal from 169 Glacier Records,” J. Oerlemans, Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands. Science 29 April 2005: Vol. 308, 675-677, doi: 10.1126/science.1107046.

[4] “Global integrated drought monitoring and prediction system,” Aengchao Hao, Amir AghaKouchak, Navid Nakhjiri, Alireza Farahmand, Nature, Scientific Data 1, Article number 140001 (2914), doi:10,1038/sdata.2014.1

 

 

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