Estimated reading time: 3 minutes
Measuring global temperatures allows scientists to determine “Global Warming,” which is important to predict our future climate. The term “global warming” is also used to refer to increases in the average temperature of the air and sea at Earth’s surface.
Global temperatures have not been increasing uniformly across the planet, but globally averaged temperatures definitely show an upward trend. (especially since the 1970’s) you can view this in the graphs below.
Why are we showing you this?
We believe everyone is entitled to their own opinion, and we respect that. This article is not be written to pursuade you. It is simply providing you the science, summarising it for, allowing you to make your own decision.
NASA – Global Temperature Index
NASA’s graph illustrates the change in global surface temperature relative to 1951-1980 average temperatures. Nineteen of the 20 warmest years all have occurred since 2001, except for 1998. The year 2016 ranks as the warmest on record (source: NASA/GISS). This research is broadly consistent with similar constructions prepared by the Climatic Research Unit and the National Oceanic and Atmospheric Administration.
Source: NASA Climate Global Climate Change, retrieved on December 9, 2020. Data download
NOAA – Climate at a Glance: Global Time Series
Climate Monitoring at NOAA’s National Centers for Environmental Information is committed to the monitoring and assessment of the state of the Earth’s climate in near real-time, providing decision-makers at all levels of the public and private sectors with data and information on climate trends and variability.
Source: NOAA National Centers for Environmental Information, Climate at a Glance: Global Time Series, published November 2019, retrieved on December 9, 2020, from https://www.ncdc.noaa.gov/cag/
European Environment Agency
How do they determine the Average Global Temperature?
To determine the Earth’s temperature, scientists combine measurements from the air above land and the ocean surface collected by ships, buoys, and sometimes satellites, too.
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. Daily anomalies are averaged together over a whole month. These are, in turn, used to work out temperature anomalies from season-to-season and year-to-year.
What data do they use to measure global temperatures?
Scientists use four major 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.
Here’s how global temperatures in three of the four datasets compare over the past 130 years. You can see they all show a warming trend.