Wednesday , June 29 2022

Climate Condition 2018: Heating, fires and flooding


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The Talk.

The 2018 Climate is the latest two-year snapshot of climate change in Australia.

It focuses on long-term trends observed that are now happening and are likely to continue to the near future, as well as significant climate events that have occurred over the last two years.

These changes are described through the latest comments from the CSIRO and Meteorology marine, atmospheric and terrestrial monitoring programs.

The report also summarizes the latest climate research from Australia and around the world. This will help inform a range of economic, environmental and social risk assessments and responses from government, industry and communities.

Multiple lines of evidence show that the climate system is changing in ways that are apparent from natural variation, and consistent with human influence on the climate. These changes affect our natural and built environment.

In particular, climate change is felt by increasing the frequency and severity of high-impact weather events such as heat heaters, extreme fire weather conditions, coastal flooding and marine heat temperatures. It is anticipated that these trends will continue.

Some of the main findings and the report are described below.

Going to big milestones

Australia's average air temperature has warmed just over 1 ℃ since national records began in 1910. Habitats around Australia have also warmed around 1 ℃ since 1910.

Average mean temperature over Australia and the seas around Australia. Meteorology Bureau, Author provided

Atmospheric concentrations of carbon dioxide are increasing worldwide. Emissions from burning fossil fuels continue to increase, and the increase in CO₂ is the main contributor, with some contribution from changes in land use.

Atmospheric CO₂ concentrations measured in Cape Grim, Tasmania (one of three main global measurements stations, alongside Mauna Loa, Hawaii, and Nunavut, Canada) have continued at levels of more than 400 parts per million (ppm) since 2016.

Moreover, the combined concentration of all greenhouse gases was greater than 500 ppm CO₂ in mid 2018. These milestones have not been crossed for at least 800,000 years, and likely 2 million years.

Changes in the atmosphere and the land

The tendency of Australian warming has led to an increase in the frequency of extreme heat events. For example, very high monthly high temperatures that occur about 2% of the time (based on the average for 1951-80) now take about 12% of time (2003-17 ).

Other elements of the Australian climate have also shown long-term changes. New analysis techniques now provide a fuller picture of changes to fire weather over time.

The total values ​​of the Forest Fire Risk Index increase over large areas of Australia. The majority of regions also saw an increase in the 10% most severe days of fire weather, and the fire seasons have extended.

The rainfall in April-October has gradually declined in South West Australia, and has declined since the 1990s in south-east Australia. In contrast, rainfall has increased in parts of northern Australia since the 1970's.

The long-term decline seen in rainfall across southern Australia has resulted in even greater reductions in a flooding. Long-term average flow flow has decreased in most regions in South Australia, and has increased in regions of northern Australia.

A warming atmosphere can hold more moisture, and this is an important driver of the increase seen in the short rainfall density, sometimes associated with flood flashes. South Australia is forecast to receive reductions in average rainfall and more time spent in drought. In the meantime, most of the country can expect an increase in intensity of rainfall.

Historically, weather and significant climate events are often due to the combined influence of a number of extreme factors at once. Higher temperatures during lower rainfall periods, for example, may exacerbate drought conditions. Temperature, drought and wind come together to create dangerous conditions.

Changes in the sea

The warmth in the Australian centers has contributed to longer-term marine heat heaters and more often – defined as periods when the surface surface temperature is much warmer than average. The oceans of the world are a vital climate moderator, taking more than 90% of the additional heat in the system – most of it is absorbed by Ocean Ocean.

Sea levels continue to increase through the combined effects of warmth heat and ice-free ice glazing and ice sheets. The average global sea level has risen more than 20cm since 1880, but the rate varies from place to place. About 25% of CO₂ emitted by human activity spread to the oceans, making them more acidic in the process.

The last two years, 2016 and 2017, have seen back-back hiding events in Great Barrier Reef parts, associated with marine heat weather events. These changes are likely to be associated with oceans warming, and are driven mainly by human influence on the climate.

An estimated sea level of 1880 estimated from tidal meters and satellites. CSIRO, author provided

Established original theory and climate model studies show that the warmth would not have occurred mainly without the increase in greenhouse gas concentrations. In addition, the current increase in temperature fits with projections made almost 30 years ago.

It is anticipated that warming will continue to the future as past emissions continue, and more greenhouse gases are dropped. It is anticipated that Australia will experience an increase in sea and air temperatures, with more hot days and sea heat temperatures, and fewer cold extremes.

It's time consuming the heat system in response to an increase in greenhouse gases, and historic emission over the past century has closed in some warmth over the next two decades, no matter what under any changes that we could make to global emissions during that period.

However, by the middle of the 21st century, the continuing emissions of greenhouse gases will result in increased warmth and associated effects, and reducing emissions will result in fewer warmth and reduced associated effects.

The average annual temperature of Australia in 1861-1900 in global climate observations and models. CSIRO, author provided

Source: The Talk. Reproduced with permission.

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