Virtually all scientists agree that the Earth has warmed a small amount since the year 1000 or, if you choose, since 1850, when instrumented temperature records became reasonably accurate and distributed in key areas of the world. An increasing number believe that any warming is so small it is indistinguishable from the noise in the environmenal data sets, and that the data have not been properly adjusted for such things as urban heat island effects (are the city temps warmer than the suburbs where you live? Has the city grown since 1850?
Have the runways increased near the temp gage at your airport since 1920?), and instrument calibration. This is particularly true of the global data set, even though “urbanization has caused regional increases in temperature that exceed those measured on a global scale, leading to urban heat islands as much as 12°C hotter than their surroundings”. Most scientists agree that warming is better than cooling and many believe CO2 provides important enhancements for forests and agriculture, even while also believing we should not be fouling our nest.