Spring sprung again this year in Sydney. We are in Summer and today is perfect spring weather. My lemon tree is covered in spring bloom again.
Spring started with a warm patch at the beginning of winter and produced a lovely crop of lemons. There was another warm Spring patch in the middle of winter and more flowers on my lemon tree.
Spring produced a regular flush of flowers then turned cold then warm producing more flowers then went cold and now the heat of summer is producing the fifth spring bloom for the year.
Is it global warming? This erratic weather and multiple blooming has occurred around here before. Over the more than twenty years I lived here, most years produced more than one bloom, making erratic weather normal. The previous few years were warmer than the first ten but this year is cool. According to the records, there were warmer periods in the 1970s and a gigantic hot period at the start of the previous century. On average, we are cooler than last century, not hotter.
The variation from year to year is greater than the variation from century to century. No individual year indicates anything. Many of the night time news broadcasts feature
record breaking ran/heat/cold/waves/wind then at the end of the news item they add
worst in the last 20 years or
worst in the last 40 years. 40 years ago appears to be a major time when the weather was worse than now in every way.
Population figures make interesting comparisons. We hear of a major disaster today when a country of 20 million people loses 2000 in a flood. Hundreds of years ago there were floods that killed 100000 people in countries with populations as low as 1 million. Some of those floods in the middle ages must have been far greater than modern day floods to kill such a high percentage of population.
The biggest recent loss of life was caused by an earthquake creating a tsunami, nothing to do with global warming. When you leave out the disasters created by earthquakes, tsunamis, and volcanic eruptions, the middle ages suffered greater disasters than today. Back then our globe was so warm that Vikings were growing grapes in Greenland.
So why do modern floods from Spring rain create so much flooding? A giant cause is the lack of trees to slow down the rain water. We strip the trees off the hills then the water floods down into our towns instead of trickling down the creeks.
We also block up the flood plains with buildings, walls, and raised roadways. Each time a flood covers a raised roadway, we make the roadway higher to keep the roadway open during floods but that makes the floods build up higher because there is nowhere else to go. We need to replace the raised roads with elevated roads to let the floods flow under the roads.
We are lucky in Sydney this year that the Spring rains are spread out over several Springs and our city can cope. There will be more years in the future when all the rain falls in one short Spring and houses will be flooded again. Sydney planning authorities will continue to build Sydney on the assumption that heavy bursts of rain never occur. I will have one giant lemon crop instead of several little crops.