Luckily our elven descendents will have advanced technology to do all the heavy work for them. Via the International Business Times:
Humans will shrink significantly because of man-made climate change if patterns from previous global warming events are followed, a team of scientists from the University of Michigan has said. Mammals decreased in size “substantially” during two ancient global warming events, known as hyperthermals.
Study leader Philip Gingerich found that dwarfing occurred in mammals including primates during the Paleocene-Eocene “thermal maximum period” 55 million years ago. Mammals also shrank in another climate change 53 million years ago.
Jawbones and tooth fossils from early hoofed mammals and primates showed that horses were about the size of small dogs today. Over the following millennia the animals grew back to their pre-warming sizes.
The reason behind the shrinking was not known, although Gingerich said that lower nutritional value of plants in elevated carbon dioxide levels might be a cause.