User:LzzeSu/Heat wave

Reduced GDP
Calculations from 2022 suggest heat waves will shrink the global economy by about 1 percent decrease by the middle of the 21st century.

Heat waves often have complex effects on economies. They reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure that is not suitable for extreme heat. In 2016, a marine heatwave in Chile and its subsequent harmful algal bloom caused $800 million (USD) in export losses for the aquaculture industry as salmon and shellfish died off.

Reduced agricultural yields
Main article: Effects of climate change on agriculture

Heat waves are a big threat to agricultural production. In 2019 heat waves in the Mulanje region of Malawi involved temperatures as high as 40 °C (104 °F). This and a late rain season scorched tea leaves and reduced yields.

Wildfires
A heat wave occurring during a drought can contribute to bushfires and wildfires. This is because a drought dries out vegetation, so it is more likely to catch fire. During the disastrous heat wave that struck Europe in 2003, fires raged through Portugal. They destroyed over 3,010 square kilometres (1,160 sq mi) of forest and 440 square kilometres (170 sq mi) of agricultural land. They caused about €1 billion worth of damage. High end farmlands have irrigation systems to back up crops.

Floods
Heat waves can also contribute to flooding. The record-breaking heat wave that afflicted Pakistan beginning in May 2022 led to glacier melt and moisture flow. These were factors in the devastating floods that began in June and claimed over 1,100 lives. Because hot air is able to carry more moisture, heatwaves may be followed by extreme rainfall especially in mid-latitude regions.

Infrastructural damage
Heat waves cause roads and highways to buckle and melt, water lines to burst, and power transformers to detonate, causing fires. A heat wave can also damage railways, by buckling and kinking rails. This can slow down or delay traffic. It can even lead to cancellations of service when rails are too dangerous to traverse by trains.

Power outages
Heat waves often lead to spikes in electricity demand because there is more use of air conditioning. This can create power outages, making the problem worse. During the 2006 North American heat wave, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformers failed, leaving thousands without power for as long as five days. The early 2009 southeastern Australia heat wave caused major power disruptions in the city of Melbourne. They left over half a million people without power as the heat wave blew transformers and overloaded a power grid.

Ecological Impacts
Researchers have predicted that roughly 10-40% of all land vertebrate species will be affected by heat waves by 2099, depending on the amount of future greenhouse gas emissions. Heatwaves present an additional form of stress and evolutionary pressure for species that already deal with habitat loss and climate change.

Species have a thermal range of tolerance that describes the temperatures where they perform best. Temperature conditions that are outside of this range may experience decreased fitness and the inability to reproduce. The species with sufficient genetic variation will be able to ensure some individuals can survive frequent days of high temperatures in the future.

Marine heatwaves may cause mass mortality in fish populations, especially for species that are better adapted to cooler temperatures. Species that have adapted to warmer temperatures may expand their range during a heatwave. These invasive species may outcompete the native species that experience higher mortality during a heatwave, which disrupts ecosystem functioning. Marine heatwaves have also been correlated with negative impacts on foundation species such as coral and kelp.