Climate change can impact human health directly and indirectly:
If temperatures continue to rise, we could hit critical thresholds that significantly accelerate climate change. In climate research, these critical thresholds are called tipping points or tipping elements. They are a part of the global climate system. Passing even just a few tipping points will have extensive environmental impacts that jeopardize the basis of life for many people, animals, and plants. Such an event could also trigger a chain reaction, where the passing of one tipping point leads to further tipping points being passed. Scientists refer to this as a feedback process.
Nine of the ten warmest years in Germany since 1881 have occurred after the year 2000 (refer to the box). Six years were already more than two degrees Celsius warmer than the long-term average at the beginning of the records (1881 to 1910), and three years were warmer by even 2.5 degrees Celsius or more.
Both internal fluctuations and external forces are causes of climate change.
The concentration of greenhouse gases in the atmosphere has been increasing ever since the beginning of industrialization at the end of the 18th century, so for more than 200 years. In the case of carbon dioxide, the main cause is the burning of carbon-based energy sources that have been created over the course of the Earth’s history (“fossil fuels”) – primarily coal, oil, and natural gas. When it comes to methane, the main sources include intensive agriculture practices (particularly livestock farming) and the use of fossil fuels (including leaks from natural gas wells and pipelines). Nitrous oxide, otherwise known as laughing gas, is also released mainly in agriculture (such as through the use of large amounts of artificial fertilizers).³
The acidity of liquids is specified by a pH value – the lower the pH value is, the more acidic the liquid. The pH value of near-surface seawater is currently around 8.1 on average worldwide, having already fallen by around 0.1 compared to the preindustrial era. While this change might sound insignificant, it translates to a 26 percent increase in acidity (because the pH scale is logarithmic). Among other things, this development threatens numerous calcifying marine organisms, such as corals, mussels, and crabs.
In Germany, one of the consequences of climate change is the increase in heavy rains. Having said that, the number of consecutive days with no precipitation is also going up, especially in summer. Both are leading to an increase in hydroclimatic extremes that pose a threat, such as droughts and floods. Scientists predict that this trend will continue into the future. According to data from Germany’s National Meteorological Service, the number of days with low soil moisture has already increased significantly since 1961. Germany’s northeast and the Rhine-Main region are being hit particularly hard by the increasing dryness of the soil.
The mean surface temperature of the North Sea in the German Bight increased by about 1.3 degrees Celsius on average between 1969 and 2017. An increase in water temperatures since 1982 of around 1.6 degrees Celsius has been measured off the German Baltic coast. The exact values vary, sometimes considerably, depending on location and water depth.
If emissions go unchecked, the rise in the global average temperature could exceed four degrees Celsius by the end of the century. At the 2015 UN Climate Change Conference in Paris, delegates decided that the global temperature increase should be limited to “well below two degrees Celsius” compared to preindustrial levels – and even to 1.5 degrees, if possible. However, we could exceed this limit in just over a decade if the current warming trend continues.