The ocean water in the Tasman sea is up to 6 C warmer than normal and it will have an unpredictable effect on the weather. The first and obvious outcome would be that the extra heat will raise the moisture content of the atmosphere by 8% for every extra degree of temperature rise and the extra heat can drive stronger storms.
Instead of rain we are in a drought so what’s happening?
New Zealand has a ridge of mountains down the West coast that effectively stops rain getting past them and we need easterly winds to bring us rain to our populated areas. The current drought is due to the increased prevalence of Westerly winds due to global warming in the Southern Ocean and the very warm weather is due to the warm water in the Tasman Sea warming the winds.
New Zealand has a ridge of mountains down the West coast that effectively stops rain getting past them and we need easterly winds to bring us rain to our populated areas. The current drought is due to the increased prevalence of Westerly winds due to global warming in the Southern Ocean and the very warm weather is due to the warm water in the Tasman Sea warming the winds.
We have also had sunny, clear skies due to the high-pressure systems coming from the west. High pressure systems are from dry air descending from 10,000 metres and effectively blot out low pressure systems which rise from the sea and rise to 3000 or 5000 metres shedding moisture and heat as they ascend.
Drought is the biggest killer to our environment and to our farming economy and food production. It can kill millions of trees, dry up streams and destroy grass and other farming produce.
Drought is the biggest killer to our environment and to our farming economy and food production. It can kill millions of trees, dry up streams and destroy grass and other farming produce.
Powerful rainstorms wash away topsoil and flood our estuaries with silt as well as causing damage to our infrastructure and homes.
So what can we expect?
The drought is already with us and we still have the warmest part of the summer months to come so we can expect it to intensify.
There must also be a big risk of powerful rainstorms causing flood damage but that is less predictable and are more likely to happen later in the summer or autumn.
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