happening by chance

See: fortuitous
References in periodicals archive ?
Rising sea levels, melting polar ice caps and glaciers and increasing amounts of carbon dioxide in our atmosphere are not just happening by chance.
1 : happening by chance or unexpectedly <an accidental discovery>
One consolation, such as it is, is that it appears there is at long last a general acceptance that we are ruining the environment and global warming is not happening by chance.