It’s 2019: reaching both New Horizons & new climate extremes
Welcome to 2019 everyone!
While some of us are only just slowly crawling back to our proverbial desks, some other ridiculous high-achievers have finally landed us on the far side of the moon, while others have organised for the New Horizons probe to travel 6.5 billion km to get some nifty images of the reddish spinning Snowman: Ultima Thule. On top of that, Queen rockstar/astrophysicist Brian May has shamed us all by also taking the time to release a new single in honour of the fly by (while some of us were proud of ourselves just for getting out to see Bohemian Rhapsody).
While we have literally been reaching new horizons out in space, back on our home planet we have been reaching some new and rather scary extremes with respect to our climate, atmosphere and extreme weather events.
The Australian Bureau of Meteorology and CSIRO recently released their fifth State of the Climate report for 2018 with the latest biennial snapshot of climate change in Australia. The report focuses on observed long-term trends that are happening now and are likely to continue into the near future, as well as significant climate events that have occurred over the past two years. These changes are described through the latest observations from CSIRO and Bureau of Meteorology marine, atmospheric and terrestrial monitoring programs.
Some of the key points made in the report include:
- climate change is being felt through an increase in the frequency and severity of high-impact events such as heatwaves, extreme fire weather conditions, coastal inundation and marine heatwaves (and are expected to continue);
- multiple lines of evidence show our climate changing in ways that are distinct from natural variability, and consistent with a human influence on climate;
- atmospheric CO₂ concentrations measured at Tasmania (one of three main global measuring stations) have persisted at levels above 400 parts per million (ppm) since 2016, and the combined concentration of all greenhouse gases exceeded the equivalent of 500 ppm CO₂ in mid-2018 – these milestones haven’t been crossed for at least 800,000 years, and likely 2 million years;
- very high monthly maximum temperatures that used to occur around 2% of the time (based on the average for 1951–80) now happen about 12% of the time (2003–17);
- annual total of daily values of the Forest Fire Danger Index is increasing over large areas of Australia. Most regions also saw an increase in the most extreme 10% of fire weather days, and fire seasons have lengthened;
- winter rainfall is still steadily decreasing in WA’s Southwest, and has decreased since the 1990s in southeast Australia (leading to even greater reductions in stream flow in our rivers). In contrast, rainfall has increased in parts of northern Australia since the 1970s;
- warming in Australia’s oceans (approximately 1 °C since 1910) has contributed to longer and more frequent marine heatwaves. The past two years, 2016 and 2017, have seen back-to-back bleaching events in parts of the Great Barrier Reef, linked to marine heatwave events.
While this is a somewhat simultaneous depressing and uplifting way to start the year, it is intended to serve as a reminder that us humans can truly have a huge effect on the world around us and do some amazing things. So let’s make sure we keep working towards making sure these kids here will be as excited about our coral reefs, woodlands and rainforests as our outer space travel.