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Thermometer

Climate change and global warming

Climate change can have both natural causes and be caused by humans. In the past, temperature fluctuations of a few degrees over several decades or centuries have always been of natural origin. Climate fluctuations are mostly caused by changes in the concentration of greenhouse gases and solar radiation.

Global warming in recent decades, however, has been caused to a considerable extent by human beings. Normally, a global temperature rise of two degrees lasts several thousand years. For such an increase, human beings did not even need a whole century. More drastic warming has become apparent in the last two decades alone.

Increase of temperatures by continents 1954 to 2023

If you want to observe rising or falling temperatures over a long period of time, you need weather stations that not only existed over the entire period, but also provided continuous data. Looking at the period of the last 70 years, only 236 of the more than 4,000 weather stations worldwide remain.

Thermometer These provide informative data from large parts of the world and show a general increase in air temperatures. Especially in the last 10 to 20 years, the temperature rose more strongly than in the previous decades. All 236 measuring stations provided continuous data during the entire observation period. Changes in these average values are therefore not due to the fact that individual stations failed for a longer period of time or new ones were added in particularly warm or cold regions. The previous 10-year average is given in each case.

In the missing Central Amerikan continent, there were no constant weather stations for the period under review, which consistently provided appropriate values.

Europe
Asia
North America
South America
Central America
Africa
Australia
The graphs show the average daily temperatures. It can be seen quite clearly that there has been a marked rise in temperatures in the most densely populated regions of the world since around the 1980s. Particularly striking are the developments in Europe, North America and Asia, where there have been significant temperature increases in some cases. In all regions, the temperature increase is consistently measurable. Only in Central and South America, as well as in Oceania, is the growth slowing down slightly in recent years.


Average temperatures

Region1954-19631964-19731974-19831984-19931994-20032004-20132014-2023
Europe7.1 °C6.9 °C7.1 °C7.3 °C7.9 °C8.1 °C8.7 °C
Asia15.8 °C15.6 °C15.6 °C15.7 °C16.3 °C16.5 °C17.0 °C
North America10.2 °C9.8 °C9.5 °C10.3 °C10.4 °C11.0 °C11.8 °C
South America18.2 °C17.9 °C18.4 °C18.3 °C18.6 °C18.4 °C18.8 °C
Central America27.0 °C27.0 °C27.2 °C27.3 °C27.7 °C27.5 °C27.6 °C
Africa19.9 °C19.8 °C19.8 °C20.3 °C20.1 °C20.8 °C20.9 °C
Australia19.1 °C19.3 °C19.2 °C19.5 °C19.5 °C19.8 °C20.3 °C
Worldwide12.2 °C11.7 °C12.0 °C12.2 °C12.6 °C12.9 °C13.7 °C


Comparison with the long-term average

Temperatures are often compared with a "long-term average" (also called a base period). This is a period of 30 years, but unfortunately it is almost useless from a statistical point of view. Because what many do not even know: it is not the directly preceding 30 years. Instead, this average is only set every 30 years and then applies for the next 30 years. The last time this happened was at the turn of the year 2020/21. So the comparison period for 2020 was the average of the years 1961 to 1990. For 2021, on the other hand, it's the years 1991 to 2020. A jump like that nullifies a comparison.

In the graphs below, we have therefore calculated our own mean from the directly preceding years in each case. The deviations of each year are shown in comparison to the average of the previous 30 years:

Europe
Asia
North America
South America
Central America
Africa
Australia
It can be clearly seen that in all regions the deviations drift more frequently into higher temperatures than into cooler ones. North America in particular has experienced some strikingly warm years in recent years. In the Southern Hemisphere, however, temperature increases have been smaller. The following graphic from NASA illustrates the global warming of surface temperatures within the last 20 years:Temperature increases over the last 20 years

Weather extremes

Both the lowest temperatures at night and the highest temperatures of the day have risen noticeably over the past decades. It is not just the average values that have changed, but also the extreme values. On the basis of the media reports, one would perhaps assume that the weather extremes would be greater in both directions, with warm months becoming warmer and cold months even colder. However, this does not seem to be the case. While the warmest month in North America between 1954 and 1963 still had an average temperature of 21.9°C, this maximum value has risen to around 22.8°C in recent years, i.e., just -2.6°C. On the other continents, the effects are even smaller.

Since this value is not a 10-year average, but the warmest month within 10 years, global warming does not seem to have too dramatic an effect, at least on temperature extremes.

Warmest months

Region1954-631964-731974-831984-931994-032004-132014-23
Europe18.0 °C17.3 °C18.3 °C17.8 °C18.8 °C19.5 °C19.3 °C
Asia25.7 °C25.7 °C25.7 °C26.3 °C26.5 °C27.5 °C27.8 °C
North America21.9 °C21.6 °C22.3 °C21.8 °C21.4 °C22.8 °C23.5 °C
South America23.0 °C23.5 °C24.1 °C22.6 °C24.2 °C22.7 °C23.4 °C
Central America28.4 °C28.4 °C28.4 °C28.9 °C29.8 °C29.0 °C29.8 °C
Africa22.1 °C22.6 °C26.8 °C23.0 °C22.6 °C23.5 °C22.8 °C
Australia24.5 °C24.4 °C25.3 °C25.3 °C24.5 °C25.1 °C25.7 °C


Coldest months

The effect is more pronounced in the coldest months: Between 1954 and 1963, the month with the lowest average temperature in North America was -2.9°C. In the last two decades, on the other hand, there has not been a single month with less than -1.0°C. So winters are actually becoming less severe. In Europe, there has been an almost equally clear increase.

Region1954-631964-731974-831984-931994-032004-132014-23
Europe-6.8 °C-4.2 °C-5.0 °C-5.9 °C-2.6 °C-4.0 °C-2.0 °C
Asia5.3 °C3.5 °C4.4 °C5.4 °C6.3 °C5.7 °C6.8 °C
North America-2.9 °C-2.0 °C-10.5 °C-1.8 °C-1.5 °C-1.0 °C-0.4 °C
South America13.1 °C13.6 °C13.8 °C13.7 °C14.3 °C14.4 °C13.4 °C
Central America25.1 °C25.1 °C25.1 °C25.3 °C26.1 °C25.8 °C25.6 °C
Africa17.4 °C16.5 °C15.1 °C16.2 °C16.7 °C17.5 °C18.1 °C
Australia11.8 °C13.6 °C12.8 °C12.5 °C13.7 °C14.1 °C14.8 °C


The figure of -10.5 °C for North America, which is out of the ordinary, is correct, by the way. This was January 1978, which surprised North America with a winter of the century. Even in Central Europe and northern Asia there were snow catastrophes with freezing cold. In North America, however, the cold wave lasted considerably longer until the end of February.


Data source: German Weather Service. Values edited, supplemented and averaged by continents. A list of the weather stations used for this evaluation can be downloaded here as a CSV file.