Trish Crossin (NT, Australian Labor Party) Share this | Hansard source

Tonight I want to discuss the implication of climate change in the Northern Territory, and I begin with the 2007 report titled State and territory greenhouse gas inventories 2005 released by the Australian Greenhouse Office. This report estimates that Australia’s greenhouse gas emissions, as a nation, totalled 559.1 million tonnes. Of this, the Northern Territory contributed two per cent, or approximately 13.5 million tonnes. When this is compared to other states—New South Wales contributed 28 per cent, Queensland, 28 per cent as well, and South Australia contributed five per cent, or 28.1 million tonnes—the Northern Territory’s contribution seems almost insignificant. Yet as a developing territory with an ever-increasing population and, as a consequence, growing sectors, it is vitally important that the Territory and Australia take action now to implement environmentally friendly policies to combat the devastating impact of climate change.

By far the largest contributor to the Territory’s gas emissions is related to agriculture, more specifically the burning of savannas, which generally occurs between May and October, which we know as the dry season. In 2005, agriculture contributed approximately eight million tonnes of greenhouse gas emissions, which is an increase of nearly two million tonnes since 1990. Stationary energy emissions created from the production of electricity and other direct combustion of fossil fuels in industry is the next highest contributor, causing four million tonnes, an increase of just over 1.5 million tonnes since 1990. Transport comes in third, contributing approximately 1.5 million tonnes—also an increase since 1990.

The Northern Territory essentially has two seasons: the wet season, defined by monsoonal showers mainly confined to the Top End, high humidity and high temperatures; and, the dry season, which traditionally sees minimal rain, low humidity and cooler temperatures. The Territory experiences many extremes in weather across its vast landscape, and climate change has an impact on all of them. Tropical cyclones are a regular threat to the Top End of the Territory, which has the Gulf of Carpentaria on the east, the Arafura Sea to the north, and the Joseph Bonaparte Gulf to the west. Given that the collection of reliable data began only in the 1970s with the advent of satellite tracking, 40 years is too short a period to have established actual incidences of tropical cyclones in certain locations. Without getting too technical, this is due to the number of El Nino and La Nina occurrences in the region and improvements in discriminating between tropical cyclones and other low pressure systems.

Statistics from the last 40 years have shown that there has been a decrease in the number of cyclones forming in waters surrounding the Top End; however, this can be attributed to the larger number of El Nino weather patterns occurring, with more cyclones traditionally forming during La Nina occurrences. The number of intense cyclones, on the other hand, has substantially increased. The intensity of the cyclone is measured by the central pressure and the wind speed, which is of most concern as this causes significant damage.

While the scientific community is deeply divided as to whether the cause for more intense cyclones is linked to climate change, there is a strong argument supporting the link. The sea surface temperature is one of a few factors needed to form a cyclone, and the temperature of the sea can determine the intensity. The warmer the sea surface, the more energy is available for tropical cyclones and, as such, the cyclone intensifies. The increase in sea surface temperatures is strongly linked to climate change. Extending from that, it could be argued that more intense cyclones are linked to climate change. The rainfall that comes with cyclones is also expected to increase, which will cause widespread flooding. One only needs to see the photographs of Maningrida—a town in the Northern Territory with a population of 2,500—after the core of Cyclone Monica passed just kilometres west of the town in April 2006 to be very fearful of a future of stronger cyclones. The town was flattened and trees were stripped bare even though the town did not experience the strongest winds the cyclone had to offer. Cyclone Monica was described by David Alexander, the senior forecaster at the Bureau of Meteorology, as one of the best developed cyclones he had ever seen—right at the top range of category 5, which is the highest category for a cyclone.

Along with cyclones comes the devastation of storm surges. A storm surge occurs because of the intense onshore winds and falling atmospheric pressure of a cyclone as it approaches or crosses the coast. The devastating effects of storm surges include severe coastal flooding, which brings sea waves further inland, eroding the coastline and destroying infrastructure. Storm surges also cause flooding of rivers and streams. The coastline and islands of the Northern Territory are particularly at risk as the coastal waters are relatively shallow. If a cyclone crosses land during high tide, the result can be catastrophic.

The Northern Territory experiences a range of temperatures across its vast landscape. Temperatures can reach a maximum average of 39.3 degrees in some areas, such as Rabbit Flat, and a minimum average of 3.4 degrees at Uluru—Ayers Rock, as we know it—in the middle of the Central Desert. An increase in temperatures has been strongly linked to climate change, and Australia in particular is experiencing an increase in temperature slightly faster than the global average. Most of the Northern Territory has warmed. Maximum temperatures have risen by approximately 0.2 degrees Celsius per decade and minimum temperatures have also risen to 0.1 degrees Celsius per decade across most of the Territory. It is clear that the average temperature rises more in the wet season than it does in the dry. The increase of average warming in Australia by 0.76 degrees Celsius since 1950 has already been associated with an increase in hot days and nights and a decrease in cold days and nights. This is an alarming trend—although I must say as a postscript, being a Territorian and coming to Canberra, that sometimes it does not feel as though there has been a decrease in cold nights! Currently, Alice Springs experiences an average of 90 days of temperatures over 35 degrees Celsius and 17 days over 40 degrees Celsius. By 2030, it is expected that the centre will experience an increase of between five and 70 days of temperatures above 35 degrees Celsius and between five and 45 days of temperatures above 40 degrees Celsius. The continuous increase of hot days and nights will increase fire risk, energy demand for air-conditioning and heat stress to humans, animals and crops.

Climate change also impacts directly on evaporation, which critically affects water storage. If there is more evaporation than rainfall, water loss will be experienced. It is a common misconception that the Territory has vast amounts of water. This is very incorrect. Below average rainfalls in past years mean there has been a failure to properly increase water resources. There is currently no danger of water restrictions at the moment, mainly because of the size of the Territory’s population; however, if Darwin had the population of a southern capital city, it would be a very different story. Rainfall will also be affected by climate change. In its report, the CSIRO states that the Northern Territory will likely experience a decrease in rainfall during the wet season as well as a decrease to the minimal dry season rainfall. The timing and magnitude of the monsoon near Darwin is also likely to be affected. To the south of the Territory, Alice Springs is expected to experience drier conditions in the near future, particularly from July to October, and a small delay to its wet season.

An article that appeared in the Canberra Times on 18 June, titled ‘North faces climate disaster’, described some concerns that leading scientists would be discussing in a two-day national conservation and climate change summit held at the Australian Academy of Science’s Shine Dome this week. This conference was organised by the World Conservation Union’s World Commission on Protected Areas and the World Wildlife Fund Australia. Dr Stuart Blanch, the director of WWF Australia’s northern conservation campaign, said in the article that studies have shown that sea levels were already affecting Torres Strait island communities and that, over the next 50 years, rising sea levels were predicted to flood more than four million hectares of costal freshwater wetlands, placing local barramundi fisheries and Aboriginal livelihoods at risk.