Australia Climate Crisis Story; Hazardous Tropical Cyclones and Storms

Tropical cyclones and severe storms are naturally occurring extreme weather events that cause significant damage. while some trends have been identified in tropical cyclone data in the past few decades, such as an increase in Atlantic cyclone activity, identifying statistically significant signals within these trends is limited by the lack of long-term, consistent observational data.

However, in the future, it is likely that the proportion of the most severe tropical cyclones, in terms of wind speeds, will increase, while the total number of tropical cyclones will likely decrease, particularly in the southern hemisphere. Increases in rainfall intensity from tropical cyclones, and severe storms in general, are likely to increase as the global average temperature increases. Similarly, increases in coastal flooding due to storm surges associated with tropical cyclones are more likely as sea level rises.

So what is a tropical cyclone? Tropical cyclones are low-pressure systems that form over warm, tropical waters and have gale force winds (sustained winds of 63 kilometers per hour or greater and gusts in excess of 90 kilometers per hour near the center). Gale force winds can extend hundreds of kilometers from the center (eye) of the cyclone. Cyclone season in Australia occurs between November and April with, on average, 10 cyclones per year, with about half of these occurring in the waters off the northwest coast and the remainder along the Top End and Queensland’s east coast.

Tropical cyclones are dangerous because they produce destructive winds, heavy rainfall, storm surges and enhanced wave action that can cause flooding of low-lying coastal areas. Cyclones pose risks to human health through injury and death from high winds, and loss of access to health and medical facilities. Coastal property and infrastructure are also vulnerable to damage and destruction from high winds. Agriculture and natural ecosystems can both suffer serious impacts from the high winds of tropical cyclones. For example, tropical cyclone Larry in 2006 destroyed many banana plantations in North Queensland, causing a sharp drop in banana production at the national level for several years. The Great Barrier Reef suffered extensive physical damage to the coral in 2011 when tropical cyclone Yasi passed over large areas of the reef.

The relationship between tropical cyclone behavior and climate change is complex, with some uncertainty in our current understanding, compounded by the lack of long-term, consistent data to monitor cyclone behavior. However, two aspects of climate change, in particular, are likely to affect cyclone behavior. First, the vertical gradient in temperature through the atmosphere, that is, the difference between the temperature near the surface of the Earth and the temperature higher up in the atmosphere, is likely to decrease as the atmosphere continues to warm. Second, the increasing temperature of the surface of the ocean affects the intensity of cyclones (along with changes in upper atmosphere conditions), both in terms of maximum wind speeds and in the intensity of rainfall that occurs in association with the cyclone.

Figure 1. Some hailstones in the 1999 Sydney hailstorm were comparable to the size of a cricket ball. (Daniel/Wikicommons).

The worst case is the storm. Severe storms range from isolated thunderstorms to large, intense low-pressure systems affecting thousands of square kilometers. In Australia, a severe storm is defined as such if it produces hailstones with a diameter of at least 2 cm, wind gusts of 90 kilometers per hour or greater, very heavy rain leading to flash flooding, or tornadoes. In Australia, most severe storms occur between September and March and occur more frequently than any other major natural hazard. Severe storms can cause heavy financial losses, and, on average, account for about one-quarter of the annual cost of natural disasters in Australia. Australia’s most costly storm occurred in Sydney’s eastern and city suburbs on 14 April 1999. This storm produced hailstones of at least 9 cm in diameter and within one hour resulted in insurance losses of around $4.3 billion.

This is the last part of climate crisis stories from Australia. I hope this will lead us to a new perspective through climate, which is no more nonsense. Let’s make a better future earth living.

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Researcher of National Battery Research Institute, The Climate Reality Leader and Author of 20 Books

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Moh Wahyu Syafi'ul Mubarok

Researcher of National Battery Research Institute, The Climate Reality Leader and Author of 20 Books