World Met Day - Understanding how our climate has changed

World Meteorological Day takes place every year on March 23. This year, the World Meteorological Organisation (WMO) is marking its 150th anniversary. To celebrate, the University of Reading is highlighting its contributions to our understanding of climate change in the past, the present and the future.

Stripes from the past for the future

Striking graphics known as the climate stripes have been shared widely across the world since they were first produced at the University of Reading in 2017. Each stripe represents the global average temperature for each year since 1850, relative to the average temperature over the period as a whole. Blue stripes represent cooler-than-average years, and red stripes indicate hotter-than-average years. The graphic is a stark visual representation of how human action has heated the climate over time.

Created by Professor Hawkins, more than one million stripes graphics have been downloaded from over 180 countries. Also appearing at Reading Festival, London Fashion Week, and on the front cover of Greta Thunberg’s Climate Book, temperature data from the past is helping to start conversations about the rapid warming of our planet.

While the climate stripes reveal how much cooler temperatures used to be in the past, they are also being used to show much warmer the world will get in the years to come. A new version of Professor Hawkins’ graphic has been included in the Intergovernmental Panel on Climate Change’s sixth Assessment Report, the final synthesis report for which was published yesterday (20 March 2023).

The stripes illustrate the different possible scenarios that future generations will face depending on the speed and scale of climate action that is taken. If drastic action is not taken sooner, and warming continues rapidly in the years ahead and beyond 2100, future generations will face more extreme weather conditions due to rising temperatures.

Saving the weather

To understand changes to weather and climate, scientists need to examine accurate data – but many old records are only stored in written archives. For example, rainfall data was recorded at the University as far back as 1901, but national data of this kind, from as far back as 1836, became available in 2022 after the University’s Department of Meteorology and 16,000 volunteers helped to restore 5.2 million weather observations. The Rainfall Rescue project was launched by the University in March 2020 and revealed some new records for extreme dry and wet months across the UK. The volunteers’ efforts also provided more context around recent changes in rainfall due to human-caused climate change.

A similar data restoration project, ‘Weather Rescue at Sea’, led by Reading’s Professor Ed Hawkins and Praveen Teleti, is currently in progress. The team are using old ships to do new science, by extracting weather records from thousands of ship logs from 1860s and 1870s. The aim is to fill large gaps in climate knowledge from previous centuries in order to make future climate projections more accurate.

Stepping back in time

A number of research projects at the University of Reading have turned back the clock thousands of years to help our understanding of how climate changes.

Sandy’s Palaeo Environments and Climate Analysis group - also known as SPECIAL - was launched by Professor Sandy Harrison in 2018 as a research project that focuses on past climate and terrestrial environmental changes. Modern data from plant traits and hydrology data from lakes is used to learn more about the past and improve projections of how the climate might change in the future.

The Centre for Past Climate Change, based at Reading, looks at how environmental changes from thousands of years ago have impacted on humans - such as how glacial periods influenced the migration of humans.

This is part one of a series of articles showing how the University of Reading has contributed to advancements in understanding climate change in the past, present and future. Check back for more articles in the build-up to World Met Day on Thursday, 23 March.