Monday, August 10th 2026
Every time a new temperature record is broken, doubts arise. How do scientists know that a particular day or summer was truly the hottest on record and that a heat wave was truly historic?
What exactly does “record heat” mean?
It depends on what the temperature is compared to. Thousands of weather stations around the world continuously monitor temperatures. A location can set a record if the temperature measured exceeds the previous high for a given day, month, or season.
Scientists determine regional and global temperature records by combining data from weather stations, ships, and ocean sounders, and then calculate average values for larger areas.
How far back these comparisons go depends on the database used. The oldest continuous series of temperature measurements in the world is the Central England Temperature Data Series, which dates back to 1659.
However, the three most comprehensive databases, run by the US Goddard Institute for Space Studies, the National Center for Environmental Information and the Hadley Center of the British Met Office, have systematically recorded temperatures since 1880.
This data is used to base claims such as: “The last decade was the warmest since records began.”
Although the Earth has experienced warmer periods and extreme temperatures throughout its 4.5 billion year history, today’s warming is remarkable in the context of the last 12,000 years of human civilization.
How do we know what the climate was like before humans and thermometers?
To reconstruct the climate of the distant past, scientists use natural data known as climate archives. They allow the reconstruction of long-term changes in temperature, precipitation and atmospheric composition.
Such archives include ice cores, tree rings, ocean sediments and fossils.
“They store information about temperature, precipitation and atmospheric composition dating back thousands and even millions of years,” climatologist Friederike Otto, founder of the research group World Weather Attribution, told DW (WWA).
The longest continuous record from ice cores comes from Antarctica and covers a period of more than a million years. In ancient air bubbles trapped in ice, researchers can measure past concentrations of carbon dioxide in the atmosphere.
“Since we know the physical laws that govern the climate system, we can also use climate models to see how changes in various factors affect climate and weather,” says Otto.
This has allowed scientists to determine that the highest concentrations of greenhouse gases throughout Earth’s history have been linked to higher global temperatures. About 56 million years ago, large amounts of carbon entered the atmosphere, possibly due to volcanic activity and the release of methane from ocean sediments, causing severe global warming.
The difference with today’s climate change is that the current warming is due to human-caused burning of fossil fuels and is happening much faster than at any time in the last million years, according to NASA.
How do scientists know if heat waves are a trend or an exception?
Climatologists analyze data collected over decades to distinguish long-term climate change from normal weather fluctuations. An unusually warm year is not evidence of a trend. However, the longer the data series, the more reliable statistical analysis and climate models are in detecting persistent patterns.
“You want consistency. You want all the available evidence to match,” says climatologist Gerald Miles of University College Dublin.
Science institutions around the world, including NASA, the US National Oceanic and Atmospheric Administration (NOAA) and the European Climate Change Service Copernicus, track global temperatures using a variety of methods and datasets. Despite the differences in approach, they all reach the same conclusion: Earth is warming, and recent years have been among the warmest on record.
Scientists also use so-called attribution studies to assess the role of climate change in causing extreme weather events. They use climate models to compare the likelihood and intensity of an event in today’s climate with a hypothetical world in which there was no human-caused warming.
The research group World Weather Attribution (WWA) applied just such an analysis to the European heat wave of June 2026. They concluded that it was the most intense heat wave ever recorded in the area they analyzed. Such temperatures, according to their estimates, would have been almost impossible in the climatic conditions of 1976, which has long been considered one of the warmest in Europe.
Which indicators should you pay attention to in a weather forecast?
Only air temperature does not fully show how heat affects the human body. That’s why weather services also publish data on subjective temperature sensation, that is, how hot it actually feels.
In the United States, a heat index is used, which takes temperature and humidity into account. The British Meteorological Office also includes the effect of wind in calculating the subjective sensation of temperature.
Why does high humidity make us feel even hotter?
When the air is very humid, it contains more water vapor, so sweat evaporates from the skin more slowly. This reduces the body’s ability to cool down, so the same temperature appears significantly warmer than in dry conditions.
Scientists also use the so-called wet-bulb temperature. It is measured by wrapping the thermometer tank with a wet cloth. As the water evaporates, the thermometer cools – in the same way that the evaporation of sweat cools the human body.
The closer the actual air temperature is to the wet-bulb temperature, the more saturated the air is with moisture and the harder it is for the body to cool down, increasing the risk of dangerous heat stress.
If the wet-bulb temperature is around 35 degrees Celsius for a long time, the human body can even overheat. when the person rests in the shade and gets enough fluids. However, dry heat is not harmless either, as it increases the risk of dehydration. /tesheshi.com/
Source: prizrenpost
