It is generally agreed that there has been a global temperature rise of just 1 Deg C since the Industrial Revolution 170 years ago.
Various scientists have done research on how this 1 deg C rise has occurred by studying ice cores. Syun-Ichi Akasofu from the International Arctic Centre at the University of Alaska Fairbanks, found that there seems to be an approximately linear increase in temperature since about 1800 to the present. Naturally, there will be fluctuations of temperature with some periods of warming and some of cooling during that time, but mathematicians can fit a straight line graph to the values. In other words, there is no general upwards trend nor any general downwards trend in temperatures. Akasofu’s research was supported by further studies by Frizsche et al in 2006 , Polyakov et al, Burroughs, and Tarrand and Nordli.