Pumping up the weather

THE year 2022 effectively tied for Earth’s fifth warmest year since 1880 - and the last nine consecutive years have been the warmest nine on record, according to the latest analysis released by NASA.

Scientists from the Goddard Institute for Space Studies (GISS), NASA’s leading centre for climate modelling in New York have reported global temperatures in 2022 were 0.89 degrees Centigrade (C) above the average for NASA’s baseline period (1951-1980), continuing the planet’s long-term warming trend. Earth is now about 1.11 degrees C warmer than the late 19th century average.

“This is alarming,” admits NASA Administrator Bill Nelson, a former Space Shuttle astronaut. “Our warming climate is already making a mark. Forest fires are intensifying, hurricanes are getting stronger, droughts are wreaking havoc and sea levels are rising.”

He says NASA is deepening its commitment to addressing climate change and adds: “Our Earth System Observatory will provide state-of-the-art data to support our climate modelling, analysis and predictions to help humanity confront our planet’s changing climate.”

“The reason for the warming trend is that human activities continue to pump enormous amounts of greenhouse gases into the atmosphere, and the long-term planetary impacts will also continue,” explains Gavin Schmidt, director of GISS.

NASA scientists, working with leading international climatologists, have determined carbon dioxide emissions were the highest on record in 2022, despite a short-lived dip in 2020 due to the Covid-19 pandemic. Levels of these human-driven greenhouse gas emissions have rebounded since.

Using the Earth Surface Mineral Dust Source Investigation instrument that launched to the International Space Station last year, they have also identified some super-emitters of methane – another powerful greenhouse gas.

Earth’s Arctic region continues to experience the strongest warming trends – close to four times the global average – according to GISS research presented at the 2022 annual meeting of the American Geophysical Union, as well as in a separate study.

Communities around the world are already experiencing the impacts that scientists see as connected to the warming atmosphere and ocean – intensified rainfall and tropical storms, severe droughts and increased storm surges.

Among many other climate-driven weather events around the world – including the UK’s hottest ever daytime temperatures which peaked at 40.3 C in Coningsby, Lincolnshire – last year brought torrential monsoon rains that devastated Pakistan and a persistent megadrought in the US Southwest. In September, Hurricane Ian became one of the strongest and costliest hurricanes to strike the continental US.

NASA’s global temperature analysis is drawn from data collected by weather stations and Antarctic research stations, as well as instruments mounted on ships and ocean buoys.

Scientists analyse these measurements to account for uncertainties in the data and to maintain consistent methods for calculating global average surface temperature differences for every year. These ground-based measurements of surface temperature are consistent with satellite data collected since 2002 by the Atmospheric Infrared Sounder on NASA’s Aqua satellite and with other estimates.

NASA uses the period from 1951-1980 as a baseline to understand how global temperatures change over time. That baseline includes climate patterns such as La Niña and El Niño, as well as unusually hot or cold years due to other factors, ensuring it encompasses natural variations in Earth’s temperature.

Many factors can affect the average temperature in any given year. For example, 2022 was one of the warmest on record despite a third consecutive year of La Niña conditions in the tropical Pacific Ocean.

NASA scientists estimate that La Niña’s cooling influence may have lowered global temperatures slightly (about 0.06 degrees C) from what the average would have been under more typical ocean conditions.

A separate, independent analysis by the National Oceanic and Atmospheric Administration (NOAA) concluded that the global surface temperature for 2022 was the sixth highest since 1880.

NOAA scientists use much of the same raw temperature data in their analysis and have a different baseline period (1901-2000) and methodology. Although rankings for specific years can differ slightly between the records, they are in broad agreement and both reflect ongoing long-term warming.

NASA’s full dataset of global surface temperatures through 2022, as well as details with code of how NASA scientists conducted the analysis, are publicly available from GISS. 

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This article by Clive Simpson was first published by Central Bylines under the title 'Heating Earth drives more extreme weather'.