In 2050, New York will resemble today’s Virginia Beach and Seattle will feel like San Francisco, shows climate change analysis
New York’s climate in 2050 will be very similar to that of current-day Virginia Beach, London will resemble today’s Barcelona, Berlin today’s Canberra, Austin today’s Peshawar, and Stockholm will resemble present-day Budapest. These are the results of the first global analysis of the shifts in climate conditions across the world’s major cities under climate change.
The researchers from ETH Zurich predict that 77% of cities around the world will experience a ‘striking’ change of climate conditions: they are very likely to experience a climate that is closer to that of another existing city than to its own current climate.
Besides, 22% of cities will experience climate conditions that do not exist today in any of the existing major cities, says the paper published in PLOS One, which covers 520 cities. Major cities refer to those that are an administrative capital or have over 1,000,000 inhabitants.
“In this study, we evaluate the global shifts in the climate conditions of cities by taking current climate data for the world’s 520 major cities (current cities) and project what they will most closely resemble in 2050. Our analysis revealed that over 77% of the world’s cities are likely to experience a shift towards the climate conditions of another major city by 2050, while 22% will shift to climate conditions that are not currently present for any major cities on the planet," says the study.
Results show that the daily difference between cities’ maximum and minimum temperatures will increase: by 2050 cities of the world will become hotter, in particular, during the winter and summer. Further, wet seasons will be wetter and dry seasons drier.
The most dramatic shift, according to the researchers, will occur in cities in the northern latitudes, with their climate in 2050 resembling today’s climate of cities over 1,000 km to their south. For example, across Europe, both summers and winters will get warmer, with average increases of 3.5˚C and 4.7˚C, respectively. These changes are equivalent to a city shifting, approximately 1,000 km further south towards the subtropics, under current climate conditions.
Cities in the tropical regions will experience smaller changes in average temperature, relative to the higher latitudes. However, shifts in rainfall will dominate the tropical cities. This is characterized by both increases in extreme rainfall events and, the severity and intensity of droughts, with the wettest months being 5% wetter and the driest months 14% drier. Overall, says the report, the tropics will become drier, and droughts will become more severe. The researchers, however, caution that the fate of major tropical cities remains “highly uncertain” because many tropical regions will experience ‘unprecedented’ climate conditions. Specifically, of all 22% of cities that will experience novel climate conditions, 64% are located in the tropics. These include Manaus, Libreville, Kuala Lumpur, Jakarta, Rangoon, and Singapore.
“As a general trend, we found that all the cities tend to shift towards the sub-tropics, with cities from the Northern hemisphere shifting to warmer conditions, and cities from the tropics shifting to drier conditions. We notably predict that Madrid’s climate in 2050 will resemble Marrakech’s climate today, Stockholm will resemble Budapest, Moscow to Sofia, Seattle to San Francisco, Portland to San Antonio, and Tokyo to Changsha,” says the paper.
Visualizing Climate Change & Making Data Relatable
The team says if carbon emissions remain unabated, the Earth will be 1.5 degree Celsius warmer by 2100, and the costs of climate change under a “business-as-usual scenario will exceed $12 trillion by 2050”.
However, say the researchers, these are just numbers, and evidence suggests that data and facts alone - which are difficult to understand - do not inspire humans to change their beliefs or actions. Instead, they say, visualization - the ability to create a mental image of the problem - is the most effective approach for motivating behavior change.
Accordingly, the Crowther Lab at ETH Zurich has created a global, interactive map. Users can click on any of the 520 cities and explore its future climate as predicted by the researchers. The researchers paired each future city with its three closest current cities. “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. By making data relatable we hope to motivate citizens and policymakers to adapt their decision-making accordingly,” says the paper.
For example, if one clicks on Toronto, the map predicts that by 2050, its climate will be most similar to that of current-day Washington, DC. The maximum temperature of the warmest month is likely to increase by 5.9°C, resulting in a mean annual temperature change of 3°C, the study predicts. Similarly, if someone clicks on Seattle, results show by 2050, its climate will resemble today’s San Francisco: the maximum temperature of the warmest month is likely to increase by 6.1°C, resulting in a mean annual temperature change of 2.6°C.
The team estimated the future conditions based on the Intergovernmental Panel on Climate Change or IPCC’s Representative Concentration Pathway (RCP4.5), which represents an “optimistic scenario.” According to this scenario, the implementation of mitigation policies would have stabilized carbon dioxide emissions by mid-century, and the mean global temperature would have increased by 1.4 degree Celsius. “Therefore, our results represent a best-case scenario,” say the researchers.
The results, says the team, not only allows one to visualize a tangible climate future of the world’s major cities, it will also enable decision-makers to see changes likely to occur in their city, within their lifetime. “Our analysis is intended to illustrate how complex climate data can be effectively summarized into tangible information that can be easily interpreted by anyone. It will help city planners to visualize the climate futures of their respective cities, facilitating efforts to establish targeted climate response strategies,” the researchers say.
Londoners, for example, can start to consider how their 2050 equivalents (for example, Barcelona today) have taken action to combat their own environmental challenges. "In 2008, Barcelona experienced extreme drought conditions, which required the importation of €22m of drinking water. Since then, the municipal government has implemented a series of ‘smart initiatives’ to manage the city’s water resources. The Mayor of London has factored drought considerations into his Environment Strategy aims for 2050, but this study can provide the context to facilitate the development of more targeted climate strategies. Besides, this information can also empower local citizens to evaluate proposed environmental policies,” say the researchers.