In recent years, extreme heat events have been on the rise, causing a lot of concern to governments and public health professionals alike. In the US alone, heat-related deaths have nearly tripled since 1980 due to extreme weather events. While much of the focus has been on the impact of these events, less is known about the origins of such extreme heat. Over the past several decades, research has suggested that the Atlantic Ocean might be a major contributing factor to these naturally occurring heat waves.
Why Is It Important To Understand Extreme Heat Events?
From extreme heat waves to extended droughts, heat-related weather events are being felt across different parts of the world. Not only do they affect the lives of people through health complications and damage to crops and structures, they can also cause huge economic losses. More importantly, such extreme weather events are likely to increase even more as the climate continues to change. So, it is important to understand the underlying causes of such events and be better prepared for when they occur.
What Are Some Factors That Contribute To Extreme Heat Events?
The sources of extreme heat events can vary. Weather phenomenon like El Nino, for example, can have a big influence on global temperatures since it brings a lot of warmer air from the Pacific into areas of the world. Natural events like volcanic eruptions or even nuclear explosions can add heat to the atmosphere. Longer-term human-induced global warming can also cause extreme weather events.
How Could the Atlantic Ocean Be Responsible For Extreme Heat Events?
Recent research suggests that while other sources of extreme heat might play a role, the Atlantic Ocean holds some of the answers as to why extreme heat waves occur. It starts with the natural phenomenon known as the Atlantic Meridional Overturning Circulation (AMOC), which plays a role in transporting heat and ocean currents between the northern and southern hemispheres. A number of factors, including changes in salinity, can impact the AMOC and cause a slow down or change in the current.
How Does the AMOC Impact Extreme Heat Events?
When the AMOC slows down, warm air is not transported as easily between the two hemispheres. This can cause a build up of heat in the atmosphere, particularly in the northern hemisphere where extreme heat events tend to occur most often. The slowed or changed current that is caused by a slowdown in the AMOC can also cause weather patterns to shift, which can influence extreme heat events.
What Are Some Evidence Supporting the Atlantic/AMOC Impact on Extreme Heat Events?
Recent studies have looked at the relationship between extreme heat events and the AMOC and have found some supporting evidence. One study, for example, examined the AMOC over the period of 1976-2017 and found that when it weakened, more extreme heat events occurred. Another study found that when the AMOC weakened during these periods, there was an increase in extreme heat events in the northern hemisphere.
How Have the Trends in Extreme Heat Events and the AMOC Changed Over Time?
Since the 1970s, records from SST and AMOC show some changes in both. While the observed changes in the AMOC are small, in terms of temperature, over long time scales a 1°C increase in SST can have significant implications for extreme heat events. Over the same period of time, an increasing trend in extreme heat events was also observed particularly in the northern hemisphere.
What Are Some of the Impacts of Extreme Heat Events?
The impacts of extreme heat events are far reaching and vary in severity depending on the geographical location, the population characteristics and the type of infrastructure present. While there are some who are more resilient to extreme weather, those living in cities, with limited access to green spaces, the elderly and children are the most vulnerable to such events. One of the biggest impacts is on human health and wellbeing, with heat-related illnesses, such as heat exhaustion and heat stroke, accounting for a significant portion of morbidity and mortality. Beyond health, extreme heat events can also cause major economic losses since many areas cannot operate, such as transport systems, electricity and water supply inconveniences, extreme weather damages to developments and infrastructure, and changes to the food system.
Can We Increase Our Resilience to Extreme Heat Events?
Given the current concerns about extreme heat events and the underlying causes, authorities and people around the world have been looking for ways to better prepare for and respond to such events. One of the most common strategies is to take preventive measures to reduce direct exposure to the heat. This includes using air conditioning, avoiding physical activities during the hottest parts of the day, and wearing light,
layered, and breathable clothing. Other strategies include greening cities by replanting urban vegetation, improving contact with urban water systems, investing in strategic cooling systems, improving public transportation services and air quality, and promoting adaptive behaviours such as alert systems and communication of risks.
What Should People Do When an Extreme Heat Event Happens?
When an extreme heat event happens, the best way to stay safe is by listening to the advice of your local authorities. This includes staying hydrated and in cool places, covering up exposed skin when outside and taking frequent breaks when engaging in physical activities. The most important thing is to be prepared and to listen to the advice of your local public health officials.
Extreme heat events are becoming increasingly common, which calls for a deeper understanding of the underlying causes. One factor that has recently come to light is the Atlantic Ocean and the phenomenon known as the Atlantic Meridional Overturning Circulation (AMOC). Recent research suggests that this circulation has a major role to play in the occurrence of extreme heat events, particularly in the northern hemisphere. With this in mind, there are increasing efforts to improve our resilience to extreme heat events by investing in preventive strategies and taking the necessary measures when extreme heat events do occur.
