2019 has been confirmed the second hottest year on record globally and the warmest year ever for the world’s oceans, rounding out the hottest decade in recorded history, as greenhouse gas concentrations continue to rise.
Globally, high temperatures were partly caused by a moderate El Niño event. El Niño events typically occur roughly every two to seven years and are characterised by warmer than normal sea surface temperatures in the tropical Pacific Ocean. Because the Pacific Ocean is so large (it covers about a third of the Earth’s surface) a huge amount of heat is released from the ocean into the atmosphere during an El Niño event. The hottest year on record, for example, occurred in 2016, when a powerful El Niño event caused enormous amounts of heat to be released into the atmosphere.
So what does it mean for New Zealand? According to NIWA’s 2019 Annual Climate Summary released in January 2019 was New Zealand’s fourth hottest year on record. For New Zealand, the effects of El Niño can be variable, but we normally expect warm and dry conditions in the east. The warm and dry conditions almost certainly contributed to the Pigeon Valley fires near Nelson.
What we learned in 2019
The Intergovernmental Panel on Climate Change released two reports in 2019 – a Special Report on Climate Change and Land, and a Special Report on Ocean and Cryosphere in a Changing Climate. The land report highlighted serious risks to food supply if temperatures continue to warm and ecosystems are likely to suffer. The oceans reported warned that sea level rise is accelerating and the current rate is “unprecedented” over the past century.
The Greenland and Antarctic ice sheets continue to melt at an increasing pace and melting permafrost has the potential to release huge amounts of carbon into the atmosphere in the coming century. A study published in January by a team of scientists led out of the University of California found that Antarctica lost mass six times faster over the past decade than between the decade after 1979, when satellite measurements began.
A report by the Intergovernmental Panel on Biodiversity and Ecosystem Services, published in May, stated that around a million species are threatened with extinction, more than ever before in human history. Changes in land and sea use, exploitation of organisms, climate change, pollution and the introduction of invasive species are all playing a part in this.
In November, the UN released their annual Emissions Gap Report, which highlighted the desperate need for countries to increase the pace of action to meet the temperature goals in the Paris Agreement. The report said that the 1.5C target is on the brink of becoming impossible unless nations around the world rapidly decarbonise their economies.
But, there is some good news, over 70 countries have now pledged to achieve net-zero emissions in the future. The International Energy Agency’s 2019 World Energy Outlook showed renewable energy generation continues to grow, making it the main contributor to new energy builds around the world.
2019 also saw a groundswell of support for climate action. A number of governments declared a climate emergency and hundreds of thousands of people came out in support of climate action in marches across the country. With the Zero Carbon Act setting long-term emissions reductions targets in place for New Zealand, the challenge lies ahead of us.