Climate change includes both the global warming driven by human emissions of greenhouse gases, and the resulting large-scale shifts in weather
patterns. Though there have been previous periods of climatic change, since the mid-20th century the rate of human impact on Earth's climate system and the global scale of that impact have been unprecedented.
Lockdown is an emergency protocol that usually prevents people or information from leaving an area. The protocol can usually only be initiated by
someone in a position of authority. Lockdowns can also be used to protect people inside a facility or, for example, a computing system, from a threat or other external event. During the 2019-20 Coronavirus pandemic, the term lockdown was used for actions related to mass quarantines. Lockdowns can limit movements or activities in a community while allowing most organizations to function normally, or limit movements or activities such that only organizations supplying basic needs and services can function normally.
Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that are
typically mild, such as the common cold, though rarer forms such as SARS, MERS, and COVID-19 can be lethal. Symptoms vary in other species: in chickens, they cause an upper respiratory tract disease, while in cows and pigs they cause diarrhea. There are yet to be vaccines or antiviral drugs to prevent or treat human coronavirus infections.