Climate change refers to the change in climatic averages. This is a long-lasting effect and impacts weather patterns and ecology. Earth's climate has experienced numerous changes over its long history. Currently, the planet is going through a period of warming. These changes are occurring faster than typical. They have been linked to human activity, namely the burning of fossil fuels which release greenhouse gasses into the atmosphere. These gases retain heat, resulting in an overall warming of the planet's atmosphere and surface.
Climate change has many implications and consequences. One is that it impacts the distribution of many species. Most species have evolved to thrive under particular climatic conditions. When these change, a species will either adapt, migrate, or die. For instance, the Canada lynx is threatened by the warming climate; its distribution reflects this. This animal thrives when there is deep snowfall. With less snowfall than normal in its historic southern range, the bulk of the lynx population has shifted northwards.
Also, when a place that was previously unsuitable for a species changes to become more favorable, that species may move into it. For instance, the phlebotomine sand fly has typically only been found in tropical and subtropical latitudes. As the climate warms, this parasitic insect has expanded well beyond its historic range into temperate zones.