Ocean floor deposits and model calculations have confirmed that in the past 3 million years, the global mean temperature has never been more than two degrees above pre-industrial levels, with fluctuating CO2 levels in the atmosphere. Since the beginning of industrialization, more CO2 has accumulated in the atmosphere through the burning of coal, oil and gas than probably ever before in the past 3 million years. Thus, in our current century, there is real threat that without effective climate policy the 2-degree limit of global warming will be breached for the first time – with far-reaching consequences.

Never before in over 1000 years the Gulf Stream System (also known as the Atlantic Meridional Overturning Circulation AMOC), has been as weak as in the last decades. PIK researchers have determined evidence of the AMOC weakening with the help of 11 proxy data series (information gathered by so called climate archives like ocean sediments, corals etc): They have compiled 11 independent data series from the North Atlantic, almost all of them from deep-sea sediment cores. They all provide a consistent picture about the flow characteristics of the Gulf Stream System and its weakening in the past 70 years. The slowdown is likely related to man-made climate change.

Over the past century, global greenhouse gas emissions have led to a sharp increase in the number of bat species in the southern Chinese Yunnan province. Bats in this area have been suggested as the original carriers of SARS-CoV-2, the virus that causes Covid-19. Scientists from Cambridge, Potsdam and Hawaii showed in a study that climate change caused shifts in the natural vegetation of the region, which allowed c. 40 bat species, carrying around 100 coronaviruses, to expand into newly suitable habitat. This process would have likely created new opportunities for viruses to be transmitted or evolve, potentially facilitating the eventual spill-over to humans. In this way, climate change may have played an important role in the outbreak of SARS-CoV-2.

Almost all of industry energy needs in Europe can be satisfied with clean power by 2050. Replacing fossil fuels with low-CO2 electricity is key to stabilize our climate. 78% of industry’s energy demand is electrifiable with technologies that are already established, Potsdam researchers showed, while 99% can be achieved with the addition of technologies currently under development. However, industry electrification leads to greenhouse gas emissions reductions only if power generation gets greener. If we do this,  in line with the European Green Deal’s targets, energy-related industry emissions would become minimal by mid-century, leaving only process emissions from chemical reactions and the like which account for around one fifth of current industry emissions.

Economic growth goes down when the number of wet days and days with extreme rainfall go up. PIK researchers found that statistically 10 more wet days in a year reduce economic growth of a region by 1%. Rich countries are most severely affected, especially the manufacturing and service sectors. The data analysis of more than 1.500 regions over the past 40 years shows a clear connection and suggests that a rising number of daily rainfall extremes, caused by human-made climate change, will harm the global economy.

Day-to-day variations in temperature, i.e. short-term variability, has a substantial impact on macroeconomic growth, according to an article by Maximilian Kotz et al, published in Nature Climate Change. If this variability increases by one degree Celsius, economic growth is reduced on average by 5 percentage-points. Particularly affected are economies in low-income regions of the global South, where seasonal temperature differences can be as small as 3°C and farmers and small business owners have not yet cultivated resilience against temperature variability. This is in contrast to Economies in Canada or Russia, where average monthly temperature varies by more than 40°C within a year and economic actors seem better prepared to cope with daily temperature fluctuations than in low-latitude regions