Dr Malini Yugendran
February 15, 2023
New Zealand has just weathered one of its worst natural disasters ever, says Prime Minister Chris Hipkins. According to Weatherwatch, cyclone Gabrielle is finally moving away from the country, but heavy rain and coastal flooding will continue to impact parts of the North Island until Thursday.
The New Zealand government has declared a state of national emergency to help respond to the disaster caused by Cyclone Gabrielle. The emergency order enables the government to streamline its response to the disaster. The emergency has been extended to the Tararua District, Northland, Auckland, Tairāwhiti, Bay of Plenty, and Hawke’s Bay CDEM Group areas. New Zealand has only previously declared a national state of emergency on two occasions, during the start of the Covid-19 pandemic and following the 2011 Christchurch earthquake.
According to the government, 2500 people have been displaced by the storm as of Tuesday.
RNZ reported that a woman has died in Putorino, northern Hawke’s Bay after a bank collapsed onto her home.
According to Vector website, there are 30,000 people without power across the Auckland region as of 8am today. This number has come down from 42,000 on 14 February 2023.
Tropical Cyclone
Tropical cyclones, known as hurricanes in the North Atlantic and eastern Pacific and typhoons in Southeast Asia and China, are storms that start in the tropics. They are powered by the heat generated when water vapour turns into rain and can have a central eye that can be about 500km in diameter. In the Southern Hemisphere, they rotate clockwise. When they approach New Zealand, they usually weaken, but they can maintain their strength if the sea surface temperature remains high. These cyclones are most severe between December and April. Climate scientist Dr. Dáithí Stone from the National Institute of Water and Atmospheric Research (NIWA) explained that tropical cyclones depend on warm ocean waters for energy. In recent years, the Tasman Sea and surrounding waters of New Zealand have been unseasonably warm due to natural factors like “La Niña” waters in the western Pacific and local ocean activity, but human-induced climate change is also contributing to this warming trend.
La Niña
La Niña is a climate pattern that naturally occurs in the Pacific Ocean. It is characterised by cooler sea surface temperatures in the equatorial region of the eastern and central Pacific. La Niña occurs when trade winds push warm surface water toward the western Pacific, causing cooler water to upwell from deeper in the ocean and cool the sea surface. It is the opposite of El Niño, which is characterised by warmer sea surface temperatures in the same region. La Niña events can happen every few years and last from several months to a couple of years. It can affect weather patterns worldwide, causing more rainfall in some regions and droughts in others.
Climate Change
Climate change can affect tropical cyclones in several ways. Greenhouse gas emissions can cause a warming of the Earth’s atmosphere, leading to warmer sea surface temperatures, which can then fuel more intense and frequent tropical cyclones. Warmer air temperatures can also increase evaporation rates, providing more moisture for tropical storms.
Scientific research has found that human-induced climate change has likely caused an increase in the intensity of tropical cyclones. The warming of the oceans is associated with a higher frequency and an increase in the number of hurricanes that rapidly intensify. Moreover, climate change can cause changes in the atmospheric conditions that influence the formation, path, and intensity of tropical storms.
Combined Effects
The waters in and around New Zealand have been warming since 2012-2013 and are now warmer than the global average. The current La Niña has been going on for a long time, the longest this century, and as a result, extreme weather systems like Gabrielle can stay closer to New Zealand and not be disrupted by cooler seas.
As climate change continues to accelerate, it is clear that more needs to be done to reduce greenhouse gas emissions and mitigate its impacts. This includes transitioning to cleaner forms of energy, reducing deforestation and land-use change, and adopting more sustainable and resilient land management practices.
Dr Malini Yugendran is an Indian Newslink Reporter based in Auckland.
