New study says average temperatures are rising in Nova Scotia

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Leaders from around the world are meeting at the United Nations Climate Change Conference in Glasgow this week to discuss our changing climate and how to tackle the growing problem moving forward.

The Conference of Parties (COP), as it's known, meets every year and is the global decision-making body set up in the early 1990s to implement the United Nations Framework Convention on Climate Change and subsequent climate agreements.

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The effects of climate change are being felt all over the planet, and Nova Scotia is no exception. 

A new study out of Nova Scotia offers even more evidence that temperatures in the province are on the rise, particularly over the past couple of decades.

The study, authored by biology professors David Garbary and Nicholas Hill from St. Francis Xavier University in Antigonish, looks at temperature records from 1961 to 2020 for 16 locations across the province. 

The data shows average temperatures in Nova Scotia have risen dramatically since 1998 when compared to the 1961-1990 normals.

In Halifax, Western Head, Kejimkujik, Greenwood and Cheticamp, increases of more than 1 C were observed. 

When breaking down the temperatures month by month, increases were more apparent in the autumn months where first frosts have been occurring later, the authors found.

On average, the 1998-2020 numbers showed an increased length of the frost-free period of 9.2 days, compared to the 1961-1990 period. The most dramatic jump was observed in Kejimkujik, where the frost-free period increased by 37 days. 

Ocean temperature impacts

Nova Scotia is almost entirely surrounded by water, and as a result, ocean temperatures are an integral part of the province's changing climate.

A separate 2014 study recognized the Atlantic coast of Nova Scotia as one of the ocean's warming hot spots.

Scientists agree that greenhouse gases are the ultimate cause for rising land and ocean temperatures around the world, but the new St. FX study also considers other impacts.

The authors found temperatures in Nova Scotia tended to be a bit cooler during El Niño events and warmer during La Niña events. Overall, however, the statistical significance during these phases was weak.

The study also references the Atlantic multidecadal oscillation, or AMO for short, which refers to changes in sea surface temperatures in the Atlantic ocean over long periods of time, roughly 60 to 80 years.

The AMO is currently in a warm phase that began in the late '90s.

Given temperatures have been rising in Nova Scotia since the '60s, the study says the positive AMO seems unlikely to explain the rise. However, the switch to a positive phase in the late '90s does "provide a partial explanation of gross temperature change."

With global temperatures expected to increase in the coming years, the study points out that it remains to be seen if future warming in Nova Scotia will be moderated when the AMO enters a negative phase.

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