Introduction Our climate future
The imminence of the climate threat requires unified actions across all sectors of society. However, a growing body of evidence suggests that facts and data, which are often hard to understand, do not necessarily persuade people to act. Behavioral change is much more likely to be inspired by visualizations that make climate issues tangible.
Our analysis is the result of a debate hosted at the Crowther Lab among an interdisciplinary group of researchers working on understanding and addressing climate change and biodiversity loss. Given the urgency to act against climate change, we spend a full day doing the required calculations, data analysis and building this report and thereby show that many answers are already here – we only must communicate them within a relatable context.
Our ResearchVisualizing climate change
In a second step, we used a multivariate approach to analyse the climate similarity of all current and future cities. When compared pairwise, we saw that only four out of 19 bioclimatic components are predominant, accounting for more than 85% of the total variation in climate: the temperate seasonality, the minimum temperature in the coldest month, the maximum temperature in the warmest month, the precipitation seasonality, the precipitation of the driest and the wettest month, as well as the temperature diurnal range. Subsequently, all other variables were dropped for the comparison.
In order to achieve our goal of visualizing the climatic changes of cities in the future to enable citizens and decision makers to grasp the impact of climate change, we paired each future city with its three closest current cities based on the dissimilarity value. This allows us to show which city will remain relatively similar to how it is now and which will shift, resembling more the current climate of another city by 2050. By keeping three cities as a basis for comparison, we ensure that at least one of the three is known to the reader.
ResultsA warmer, drier world
Tropical regions will experience smaller changes in temperature, but significant shifts in precipitation with the wettest months being 5% wetter and the driest months 14% drier. Overall the tropics will become drier and droughts more severe. However, these predictions are to be considered as best case and contain a high proportion of uncertainty as out of the 22% of cities that will experience novel climate conditions, 64% are located in the tropics.
Generally speaking, we observed changes towards less temperature seasonality, with higher maximal and minimal temperatures during the year, as well as higher precipitation seasonality with higher precipitation in the wettest but lower in the driest month. The daily difference between cities’ maximum and minimum temperatures will increase. In brief, by 2050 cities of the world will have become hotter, in particular during the winter and the summer. Wet seasons will be wetter and dry seasons drier.
We believe that it is through this comparison with current cities and their known struggles with their climate conditions that the need to act becomes tangible. In 2008, for example, Barcelona experienced extreme drought with severe implications on the well-being of its population and the consequent need to import €22m of drinking water. In 2017, the Mayor of London has factored drought considerations into the city’s Environmental Strategy aims for 2050.
Even though our analysis contains uncertainties and the predictions may change as Earth system models are refined, it may provide the context to facilitate the development of more targeted climate strategies.
To learn more, read the full paper here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217592