Much of that is just from skeevy sites you are visiting that try to hijack your browser with ads and such. But if you get on a loop with one of those you can force quit Safari force quitting Safari from the Activity Monitor app. Then hold the shift key the next time you launch Safari to prevent yourself from being directed back to that same site.
Also, you may be infected with adware. Try running this adware removal tool to clean off any adware.