Genetic diversity is the variation in the genetic makeup of a population. It is measured by the number of different alleles at a given locus, or by the average genetic similarity between two individuals.

Genetic diversity is important for a number of reasons. It allows populations to adapt to changing environmental conditions, it increases the productivity of ecosystems, and it reduces the risk of disease outbreaks.

Climate change threatens genetic diversity in a number of ways. It can lead to the loss of habitats, which can reduce the size of populations and increase the risk of inbreeding. It can also fragment populations, which can prevent gene flow and lead to the loss of genetic diversity. Finally, climate change can increase the rate of mutation, which can introduce new alleles into a population and disrupt the balance of genetic diversity.

Climate change has affected genetic diversity in a number of ways. For example, the loss of coral reefs has led to a decline in the genetic diversity of reef fish, the fragmentation of forests has led to a decline in the genetic diversity of tree species, and the warming of the Arctic has led to a decline in the genetic diversity of polar bears.

There are a number of things that can be done to protect genetic diversity from climate change. These include reducing greenhouse gas emissions, protecting and restoring habitats, and promoting sustainable land use practices.