Earlier this month, Twitter’s data centers were tested by the extreme heat that passed through California. On Labor Day weekend, when temperatures in the state hit up to 116 degrees Fahrenheit, one of the company’s key server farms in Sacramento suffered a weather-related outage. 

Luckily, the social media platform didn’t see any noticeable disruptions. But according to an internal memo obtained by CNN on September 12, if another data center had gone out at the same time, then many Twitter users would’ve experienced service blackouts. 

Twitter isn’t the only company whose servers have become vulnerable to unprecedented high temperatures. Over the summer, Google, Oracle, and Amazon Web Services all struggled to keep their data centers operational in the UK as temperatures climbed above 100 degrees Fahrenheit. Google and Oracle specifically experienced issues with their cooling systems at their facilities in London, Protocol reported. 

[Related: Whistleblower tells Congress that Twitter has a spy problem]

During this period, many companies turned off their high-power computers to prevent heat damage, according to New Scientist. To keep services running, some facilities operators have resorted to manually hosing down equipment to cool it down, Bloomberg explained. 

Data centers are buildings filled with powerful computers that can run a wide range of services. It’s where data from applications, databases, and more gets processed, stored, and distributed. It also has infrastructure needed for networking, power, and cooling the indoor environment. 

[Related: Our infrastructure can’t handle climate disasters. We need to build differently.]

These facilities run their devices off electricity from the same grid that supplies nearby homes and businesses. Because large data centers process loads of requests, they use a lot of computing power and generate a lot of heat. So, to prevent servers from frying, many facilities have a dispersed water-based cooling system that takes up extra energy. When it’s hotter outside, these systems have to work much harder, further straining the demand on the grid. 

To get around the cooling issue, some companies have been building new data centers in cold-weather countries like Finland, Sweden and Iceland. Microsoft has even contemplated placing their facilities in the ocean (that project is currently still in the research phase). But the challenge there is that the computers will be located farther away from their users, slowing down the speed of certain services. 

[Related: Are ‘water positive’ pledges from tech companies just a new kind of greenwashing?]

Data centers have always had issues with sustainability. They’ve been criticized for their ravenous energy consumption and rampant water use. Now, with mass temperature fluctuations and increasing natural disasters brought on by climate change, many of these problems have become more pronounced. Drought-prone communities have pushed back against development of new data centers in places like California and Arizona. Energy prices and soaring temperatures will only continue to make daily operations difficult for Twitter and other corporations. 

One solution would be to overhaul the conventional design of server farms. For years, government agencies like the Department of Energy have been advising engineers on ways to make these facilities more energy efficient. Other organizations have proposed using the heat from data centers to power homes. As countries struggle to handle the implications of energy use on climate change, big tech companies like Google and Amazon have promised to transition much of their operations, including for their data centers, to renewable energy. Twitter, in a post on Earth day this year, said that it aims to use 100 percent carbon neutral energy to power all of its data centers by the end of this year.