1.what has been the hottest year on record worldwide? 2.how do the researchers gather data for worldwide temperatures? 3.where does 2006 rank in the hottest years on record? 4.what do you notice about the trend of the top warmest years?

Answer 1 : According to the NASA and the NOAA 2016 was the hottest year on the record worldwide.

Answer 2 : To get a complete picture of Earth’s temperature, scientists combine measurements from the air above land and the ocean surface collected by ships, buoys and sometimes satellites.

The temperature at each land and ocean station is compared daily to what is ‘normal’ for that location and time, typically the long-term average over a 30-year period. The differences are called an ‘anomalies’ and they help scientists evaluate how temperature is changing over time, a ‘positive’ anomaly means the temperature is warmer than the long-term average, a ‘negative’ anomaly means it’s cooler

Here are four datasets  to study global temperature.The UK Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit jointly produce HadCRUT4 . In the US, the GISTEMP series comes via the NASA Goddard Institute for Space Sciences (GISS), while the National Oceanic and Atmospheric Administration (NOAA) creates the MLOST record. The Japan Meteorological Agency ( JMA) produces a fourth dataset.  

Answer 3 : the NASA Goddard Institute for Space Studies (GISS) in New York City have found that 2006 was the fifth warmest year in the past century

Answer 4 : We can notice about the trend of the top warmest years that an increase in atmospheric greenhouse gases, primarily carbon dioxide from the burning of fossil fuels, continues to drive this long-term warming trend. It is responsible for warming both the atmosphere and the oceans as greenhouse gas concentrations continue to grow. We can notice that it is very hot in the pole,for example we have a faster warming in the Arctic than the rest of the world.

Source: Cowtan & Way (2013).