Global warming causes animals to shrink?

Except that global warming has caused people to grow and global cooling has caused people to shrink.

In the global-warming-causes-shrinking-corner, consider this media release from University of London researchers:

The way in which global warming causes many of the world’s organisms to shrink has been revealed by new research from Queen Mary, University of London.

Almost all cold-blooded organisms are affected by a phenomenon known as the ‘temperature-size rule’, which describes how individuals of the same species reach a smaller adult size when reared at warmer temperatures. But until now, scientists have not fully understood how these size changes take place.

Writing in the journal The American Naturalist, Dr Andrew Hirst and colleagues from Queen Mary’s School of Biological and Chemical Sciences explore this unusual shrinking effect in more detail, and show conclusively how it occurs.

Funded by the Natural Environment Research Council, the study was carried out using data on marine planktonic copepods. These tiny crustaceans are the main animal plankton in the world’s oceans and are important grazers of smaller plankton and a food source for larger fish, birds and marine mammals.

By gathering together more than 40 years of research studying the effect of temperature on these organisms, their results show that growth rate (how fast mass is accumulated) and development rate (how fast an individual passes through its life stages) are consistently decoupled in a range of species, with development being more sensitive to temperature than growth.

Dr Hirst explains: “We’ve shown that growth and development increase at different rates as temperatures warm. The consequences are that at warmer temperatures a species grows faster but matures even faster still, resulting in them achieving a smaller adult size.

“Decoupling of these rates could have important consequences for individual species and ecosystems,” he added.

The team’s findings suggest that rates fundamental to all organisms (such as mortality, reproduction and feeding), may not change in synch with one another in a warming world. This could have profound implications for understanding how organisms work, and impact on entire food webs and the world’s ecosystems.

Although the team’s findings disagree with earlier assertions of many macro-ecologists, they clearly explain the smaller sizes associated with the ‘temperature-size rule’. They hope their work will help those investigating the potential impacts of climate change on the natural world.

Now from the global-warming-is-a-hoax corner consider this report from Ohio State researchers entitled “MEN FROM EARLY MIDDLE AGES WERE NEARLY AS TALL AS MODERN PEOPLE“:

Northern European men living during the early Middle Ages were nearly as tall as their modern-day American descendants, a finding that defies conventional wisdom about progress in living standards during the last millennium.

“Men living during the early Middle Ages (the ninth to 11th centuries) were several centimeters taller than men who lived hundreds of years later, on the eve of the Industrial Revolution,” said Richard Steckel, a professor of economics at Ohio State University and the author of a new study that looks at changes in average heights during the last millennium.

“Height is an indicator of overall health and economic well-being, and learning that people were so well-off 1,000 to 1,200 years ago was surprising,” he said.

Steckel analyzed height data from thousands of skeletons excavated from burial sites in northern Europe and dating from the ninth to the 19th centuries. Average height declined slightly during the 12th through 16th centuries, and hit an all-time low during the 17th and 18th centuries.

Northern European men had lost an average 2.5 inches of height by the 1700s, a loss that was not fully recovered until the first half of the 20th century.

So unlike whatever happened to the plankton in the University of London work, in real life, humans have been taller when its warmer (i.e., the pre-Little Ice Age and post-Little Ice Age) and shorter when it’s cooler (i.e,. Little Ice Age).