2021 tied for sixth warmest year in continued trend, analysis shows
NASA
 |
| Screenshot from new StormTools database showing Charlestown's coastline. Areas in dark blue will be innundated by a 5 foot rise in sea level. Other shades of blue show flooded areas during 25-year and 100-year coastal storms. These are all likely events, not as Richard Sartor would put it, "unknown unknowns" |
Earth's global average surface temperature in 2021 tied with 2018 as the sixth warmest on record, according to independent analyses done by NASA and NOAA. Collectively, the past eight years are the warmest years since modern recordkeeping began in 1880.
Continuing the
planet's long-term warming trend, global temperatures in 2021 were 1.5 degrees
Fahrenheit (0.85 degrees Celsius) above the average for NASA's baseline period,
according to scientists at NASA's Goddard Institute for Space Studies (GISS) in
New York. NASA uses the period from 1951-1980 as a baseline to see how global
temperature changes over time.
Collectively,
the past eight years are the warmest years since modern recordkeeping began in
1880. This annual temperature data makes up the global temperature record --
which tells scientists the planet is warming.
According to
NASA's temperature record, Earth in 2021 was about 1.9 degrees Fahrenheit (or
about 1.1 degrees Celsius) warmer than the late 19th century average, the start
of the industrial revolution.
"Science leaves no room for doubt: Climate change is the existential threat of our time," said NASA Administrator Bill Nelson. "Eight of the top 10 warmest years on our planet occurred in the last decade, an indisputable fact that underscores the need for bold action to safeguard the future of our country -- and all of humanity.
NASA's scientific research about how Earth is changing and getting warmer will guide communities throughout the world, helping humanity confront climate and mitigate its devastating effects."
This warming trend around the globe is due to human activities that have increased emissions of carbon dioxide and other greenhouse gases into the atmosphere. The planet is already seeing the effects of global warming: Arctic sea ice is declining, sea levels are rising, wildfires are becoming more severe and animal migration patterns are shifting.
Understanding how the planet is changing -- and how
rapidly that change occurs -- is crucial for humanity to prepare for and adapt
to a warmer world.
Weather stations, ships, and ocean buoys around the globe record the temperature at Earth's surface throughout the year. These ground-based measurements of surface temperature are validated with satellite data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite.
Scientists analyze these measurements using computer algorithms to deal with uncertainties in the data and quality control to calculate the global average surface temperature difference for every year.
NASA compares that global mean temperature to its baseline period
of 1951-1980. That baseline includes climate patterns and unusually hot or cold
years due to other factors, ensuring that it encompasses natural variations in
Earth's temperature.
Many factors
affect the average temperature any given year, such as La Nina and El Nino
climate patterns in the tropical Pacific. For example, 2021 was a La Nina year
and NASA scientists estimate that it may have cooled global temperatures by
about 0.06 degrees Fahrenheit (0.03 degrees Celsius) from what the average
would have been.
A separate,
independent analysis by NOAA also concluded that the global surface temperature
for 2021 was the sixth highest since record keeping began in 1880. NOAA
scientists use much of the same raw temperature data in their analysis and have
a different baseline period (1901-2000) and methodology.
"The complexity
of the various analyses doesn't matter because the signals are so strong,"
said Gavin Schmidt, director of GISS, NASA's leading center for climate
modeling and climate change research. "The trends are all the same because
the trends are so large."
NASA's full
dataset of global surface temperatures for 2021, as well as details of how NASA
scientists conducted the analysis, are publicly available from GISS (https://data.giss.nasa.gov/gistemp).
GISS is a NASA
laboratory managed by the Earth Sciences Division of the agency's Goddard Space
Flight Center in Greenbelt, Maryland. The laboratory is affiliated with
Columbia University's Earth Institute and School of Engineering and Applied
Science in New York.
For more information about NASA's Earth science missions, visit: https://www.nasa.gov/earth
 |
| WPRI graphic |
Overall warming with reduced seasonality: temperature change in New England,
1900–2020
By Stephen S.
Young and Joshua S. Young, Salem State University
The ecology, economy, and cultural heritage of New England is grounded in its seasonal climate, and this seasonality is now changing as the world warms due to human activity.
This
research uses temperature data from the U.S. Historical Climatology Network
(USHCN) to analyze annual and seasonal temperature changes in the New England
region of the United States from 1900 to 2020 at the regional and state levels.
Results
show four broad trends:
(1)
New England and each of the states (annually and seasonally) have warmed
considerably between 1900 and 2020;
(2)
All of the states and the region as a whole show three general periods of
change (warming, cooling, and then warming again);
(3)
The winter season is experiencing the greatest warming; and
(4)
The minimum temperatures are generally warming more than the average and
maximum temperatures, especially since the 1980s.
The
average annual temperature (analyzed at the 10-year and the five-year average
levels) for every state, and New England as a whole, has increased greater than
1.5 °C from 1900 to 2020.
This
warming is diminishing the distinctive four-season climate of New England,
resulting in changes to the region’s ecology and threatening the rural
economies throughout the region.