Why is everyone talking about 1.5 degrees?

The media are full of reports about the omi­nous tem­per­a­ture of 1.5°C. Why is this like that? An expla­na­tion in sim­ple terms.

The 1.5 degree tar­get or lim­it denotes a thresh­old at which the con­se­quences of cli­mate change can still be rea­son­ably man­aged. If this lim­it is exceed­ed, this will have seri­ous unfore­see­able and irre­versible con­se­quences for large parts of mankind. These severe con­se­quences are e.g. long-last­ing droughts, heat extremes, heavy rain events or floods. How such events look like is not only shown by the flood dis­as­ter in the Ahr val­ley, but also by the cur­rent heat wave in India and Pak­istan with tem­per­a­tures of 50°C.

The choice of 1.5°C is not an arbi­trar­i­ly cho­sen tem­per­a­ture, but this goes back to a spe­cial report of the Inter­gov­ern­men­tal Pan­el on Cli­mate Change, which lists the ben­e­fits that com­pli­ance with this lim­it would mean. This tem­per­a­ture refers to the aver­age tem­per­a­ture from before indus­tri­al­iza­tion, which occurred in the years 1850–1900. This is referred to as man-made cli­mate change.

Why is the empha­sis on “man-made” impor­tant? Quite sim­ply, if it has been caused by humans, humans can also coun­ter­act it. There are now many, many stud­ies from the sci­en­tif­ic com­mu­ni­ty that can prove that human actions have caused the cli­mate to change.

Now the World Mete­o­ro­log­i­cal Orga­ni­za­tion (WMO) has pub­lished a report that says the aver­age glob­al tem­per­a­ture could reach the 1.5‑degree mark for the first time as ear­ly as 2026. That’s four years from now.

Some sci­en­tists speak of a “tip­ping point” at which our ecosys­tem changes so much that irre­versible effects occur. These include, for exam­ple, ris­ing sea lev­els and the melt­ing of large glac­i­ers.

It is empha­sized that exceed­ing the 1.5‑degree lim­it once is not the same as exceed­ing it per­ma­nent­ly. This report is a reminder to all of us, but espe­cial­ly to politi­cians and indus­try, that action must final­ly be tak­en. Green­house gas emis­sions must be reduced now. And in a clear­ly notice­able amount. The cli­mate is not wait­ing for politi­cians to fin­ish their dis­cus­sions.

By the way: Ger­many has already used up all its resources on May 04. At least the­o­ret­i­cal­ly, because this is indi­cat­ed by Earth Over­load Day, which is a day of action by the Glob­al Foot­print Net­work orga­ni­za­tion. This is to point out that we con­sume more resources than our earth can pro­vide us humans.

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