Glossary | Climate Lexicon P

carbon-connect AG Climate Glossary with common technical terms, abbreviations and explanations on the topics of the environment, climate protection and CO2 compensation.


Permafrost forms in areas where the temperature stays below 0 degrees Celsius for many years. The area covered by permafrost in the Northern Hemisphere makes up about 24% of the landmass. This is an area of about 23 million km2.

pH Value

The pH value is a measurement of the acidic or basic character of water or a solution. Pure water has a pH value of 7 (neutral). Acidic water has a pH value of less than 7, and a pH of over 7 is considered basic. Lemon juice has a pH of 2.4 (acid), pure water a value of 7 (neutral), and bleach a pH value above 12 (alkaline).


The abbreviation ppm is a measurement for concentration and stands for "parts per million". In 2015, the concentration of carbon dioxide in the atmosphere was about 400 ppm. In other words, there were about 400 parts of CO2 per million air particles.