May 2025 S M T W T F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Archives
Categories
WeatherGuys Links
Category Archives: Climate
Should we stop climate research?
Scientific evidence for slow, ongoing, systematic warming of Earth’s atmosphere is unequivocal. This conclusion comes from evidence-based science and a physical understanding of that evidence. Regular scientific assessments of global and regional climate began in the 1970s. These assessments, along with a physical understanding of the atmosphere, show that the impact of human activities on this warming has evolved from theory to established fact. This is not a radical political statement; it is a firm conclusion based on the analysis of carefully considered observations.
Burning fossil fuels generates greenhouse gases, which are transparent to solar radiation but absorb large amounts of terrestrial infrared radiation that results in warming the atmosphere. The planet’s average surface temperature has risen about 2 degrees Fahrenheit since the late 1800s. Most of that warming has occurred in the past 40 years. Continue reading
How do we measure global cloud cover?
Because clouds are involved in the global water cycle as well as our planet’s energy gains and losses, they constitute an important component of our atmosphere, weather, and climate.
Determining global cloud cover requires observations that cover the entire planet. Observations from weather satellites provide a modern estimate of the global cloud cover. These satellites are operated by several countries and their data is shared through international agreements. Discrimination between clear and cloudy regions is a crucial first step in most applications of satellite data, such as estimating ocean temperature or assessing the health of land vegetation. Continue reading
Beyond the headlines, what else has been happening in the weather lately?
There has certainly been a lot of interesting and, in many cases, devastating weather around the country in the past couple of weeks. The heavy snow in parts of the country that don’t often see it along with the California wildfires have caught the attention of lots of us in the first days of the new year.
But in the background is a rather remarkable one-week stretch that occurred in the last week of December. Continue reading
Was 2024 an interesting weather year for Wisconsin?
Yes, 2024 was a very interesting year. The statewide average temperature was 31.4 degrees Fahrenheit, which is 12.2 degrees warmer than the 1991-2020 normal. December 2023 to February 2024 was our warmest winter since record-keeping began in 1895. The statewide average temperature for the winter was 28.3 degrees, surpassing the previous record by 2 degrees.
Wisconsin’s average temperature during November 2024 was 38.7 degrees, which is 7.1 degrees above the November average temperature. Seventy out of Wisconsin’s 72 counties recorded a November 2024 average temperature much above average. Overall, 2024 is on track to be Wisconsin’s warmest year on record. Continue reading
Does the warmest autumn on record mean anything about the coming winter?
In the past several years we have occasionally mentioned our tracking of the areal extent of air colder than minus 5 degrees centigrade at about 1 mile above the surface of the Earth. This measurement has proven to be a very valuable addition to the collection of metrics of global warming. We have particularly commented on the wintertime (December, January and February) average of this extent measured over the entire Northern Hemisphere, noting that since 1948 the wintertime average extent has systematically decreased.
We have also been tracking this variable throughout the autumn over all these years and can report that this fall (Sept. through Nov. 30) recorded the smallest average areal extent of this cold air since at least 1948. That means we have just experienced the warmest Northern Hemisphere autumn in at least the past 77 years. Continue reading
