A report in the 'Nature Climate Change' journal has claimed that rising global temperatures and changes in weather patterns have knock-on effects which are already stunting the growth of a wide range of species worldwide.
Species which are unable to adapt quickly enough are at risk of extinction as ecosystems shift dramatically, altering the balance of food and other resources needed for survival, according to the report.
The change could also have a major impact on expanding human population, with major food sources like fish likely to reduce in size and crops expected to grow smaller and less reliably than today, say the scientists.
David Bickford at the National University of Singapore, the report's lead author, was quoted by 'The Daily Telegraph' as saying, "The consequences of shrinkage are not yet fully understood, but could be far-reaching for biodiversity and humans alike.
"Because recent climate change may be faster than past historical changes in climate, many organisms may not respond or adapt quickly enough. This implies that species may go extinct because of climate change."
The scientists argue that warmer and drier weather causes plants and animals to reach smaller sizes, while more variable rainfall levels raise the risk of failed crop years. Over the past century, animals including toads, tortoises, blue tits and red deer have all started to reduce in size, they said.
Lower levels of sea ice have even resulted in polar bears getting smaller, according to the report.
However, one major issue is that not all plants and animals will shrink at the same rate, throwing finely balanced ecosystems out of kilter, the scientists said.
Reduced food supplies are likely to mean that animals at the top of their food chains, including humans, will grow to smaller sizes, have fewer offspring, and be more vulnerable to disease, they added.
During the past century global average temperatures have risen by almost 1C, and climate experts predict 7C of warming by 2100.
