Climate change is accelerating at unprecedented speed and is already affecting nearly all life and development on earth. The world average surface temperature has risen by about 0,9 degrees Celsius since the late 19th century. Furthermore, the five warmest years ever recorded have occurred since the year 2000. 

In addition to the effect of surface warming, the oceans temperature (top 700 meters) has increased by more than 0,4 degrees Fahrenheit since 1969. 

More than 97 percent of actively publishing climate scientists agree, that global warming is most likely an effect of human activity on earth. 

Sources: 

https://climate.nasa.gov/evidence/

https://climate.nasa.gov/scientific-consensus/