CropKep

22/11/2021

‘A vigorous cold front’: why it’s been so cold this week, with more on the way
Across most of Australia this week, people have woken up and thought “Goodness, it’s cold.” Summer doonas are being changed to winter doonas. Heaters are being switched on. Ugg boots are being dug out of storage.

Yes, some of this is normal seasonal transition. But at least a portion of it is due to a particularly vigorous cold front that swept across southeast Australia over the weekend, dragging with it an unusually cold air mass.

Canberra on Monday night got to -2.6℃, which is a new record low for this monitoring station for April (the previous lowest for April was -1.9℃ in April 2013).

Another strong cold front is forecast to move across the area on Thursday into Friday with snowfall to 800 metres for Tasmania, and about the Alpine peaks of New South Wales and Victoria.
For any families making the most of the last weekend of school holidays by camping or being outdoors — pack the thermals, because the mornings are going to be cold!

Frost is forecast across many parts southeast inland, away from the coast — but the days will milder, with blue skies and light winds. In other words, a beautiful Autumn day. Coastal campers can expect a bit more cloud around and even the chance of a shower.

Read more: Here's how a complex low-pressure system sent temperatures plummeting

22/11/2021

More people die in winter than summer, but climate change may see this reverse
Climate change not only poses enormous dangers to the planet, but also harms human health. In our study published today, we show some of the first evidence climate change has had observable impacts on Australians’ health between 1968 and 2018.

We found long-term heating is associated with changed seasonal balance of deaths in Australia, with relatively more deaths in summer months and relatively fewer deaths in winter months over recent decades.

Our findings can be explained by the gradual global warming associated with climate change. Over the 51 years of our study, annual average temperatures increased by more than 1°C in Australia. The last decade (2011 to 2020) was the hottest in the country’s recorded history.

If we continue on this trajectory, we’re likely to see many more climate-related deaths in the years to come.
What we did and found
Using the Australian Institute of Health and Welfare, the Australian Bureau of Statistics and other sources, we gathered mortality data for people aged 55 and over between 1968 and 2018. We then looked at deaths in summer compared to winter in each year.

We found that in 1968 there were approximately 73 deaths in summer for every 100 deaths in winter. By 2018, this had risen to roughly 83 deaths in summer for every 100 deaths in winter.

The same trend, albeit of varying strength, was evident in all states of Australia, among all age groups over 55, in females and males, and in the three broad causes of death we looked at (respiratory, heart and renal diseases).
Hot and cold weather can have a variety of direct and indirect effects on our health. Winter death rates generally exceed those in summer months because infectious diseases, like influenza, tend to circulate more in winter. Meanwhile, heat stress can exacerbate chronic health conditions including heart disease and kidney disease, particularly for older adults.

But the gap between cold-related deaths and heat-related deaths appears to be narrowing. And when we compared deaths in the hottest summers with the coldest winters, we found particularly warm years increase the likelihood of seasonal mortality ratios approaching 1 to 1 (meaning equal deaths in summer and winter).

With summers expected to become hotter, we believe this is an early indication of the effects of climate change in the future.

Read more: Too hot, heading south: how climate change may drive one-third of doctors out of the NT

22/11/2021

What climate change means for southern Ontario and Québec
The Intergovernmental Panel on Climate Change (IPCC) recently released the first report of the sixth assessment cycle. Three others will follow in 2022.

This volume of nearly 4,000 pages has observations on climate change from the past 150 years and projections for climate change up to the end of this century. It is being published 31 years after the first assessment cycle and eight years after the fifth assessment cycle.

Overall, this latest report does not provide major new insights into climate change or the impact of human activity on it. It does, however, improve our understanding of the human role in climate change and reduce uncertainty about anticipated future impacts. By refining observation methods and improving the accuracy of climate models, the report makes it possible to better define the future impacts on the densely populated areas of southern Ontario and Québec.

We are professors of construction engineering and members of the HC3 — Hydrology Climate Climate Change Laboratory at the École de technologie supérieure de Montréal. The laboratory specializes in the study of hydrology, climate and the impact of climate change on water resources.
Warming twice as fast
The average global temperature on Earth has increased 1.1 C since the pre-industrial era. Climate projections predict a temperature increase between 2 C and 3.5 C by the end of this century. This does not take into account the most pessimistic greenhouse gas emissions scenario, which is now considered improbable by most experts.

Read more: 5 things to watch for in the latest IPCC report on climate science

This warming, however, is not geographically uniform. On the whole, southern Ontario and Québec are warming twice as rapidly as the rest of the world. Northern regions are warming three times as fast.

The faster warming is mainly because of the ice–albedo feedback loop that is linked to the progressive loss of snow cover. This process means, among other things, that solar radiation, which is normally reflected by the snow, will be absorbed instead. We should therefore anticipate an average annual warming of 3 C to 6 C over southern Québec by the end of the century.

However, the warming will not be evenly distributed across the seasons. Winters will warm significantly more than summer. This means future winters will be 4.5-8 C warmer, with less snow cover and a decrease in spring flooding from melting.

22/11/2021

22/11/2021