Animals and plants are shrinking due to the effects of climate change, scientists have warned.

Increasing global temperatures are impacting on food sources, changing ecosystems and making resources scarcer.

As such, the warmer weather is resulting in smaller-sized plants and animals.

Writing in the journal Nature Climate Change, Dr David Bickford and Jennifer Sheridan argue that a shifting trend in animal and plant size could impact on human populations, especially if food sources, such as fish, are affected.

"The consequences of shrinkage are not yet fully understood, but could be far-reaching for biodiversity and humans alike,” they wrote.

"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."

According to the article, polar bears are shrinking in size due to the loss of sea ice, while sheep, deer, tortoises, gulls, woodrats and trees are also getting smaller.

During the past 100 years, the average global temperature has risen by 1C. However, scientists predict an increase of 7C by 2100, with the consequences of such a dramatic rise likely to have a devastating affect on both plants and animals.