Of the four past record-breaking years, 2016 was the hottest. The World Meteorological Organization says temperatures that year reached a global average of 1.2 degrees Celsius above pre-industrial levels. It says the increased warming in the atmosphere was influenced by a strong El-Nino event, which causes sea temperatures to rise in the tropical Pacific.
Temperatures in 2018 dipped to 1 degree Celsius above pre-industrial levels. But meteorologists say the ranking of individual years is less important than the long-term temperature trend in gauging climate change.
The WMO says other factors besides temperature are involved in changing climate. WMO spokeswoman Claire Nullis says extreme weather events also play an important role.
“Obviously, as we continue in 2019, we are seeing more extreme weather… in different parts of the world, including dangerous and extreme cold in North America, record heat and wildfires in Australia, high temperatures and rainfall in parts of South America,” Nullis said.
While Australia was baking in its warmest January on record, a cold weather front was gripping parts of the eastern United States. Nullis says freezing temperatures do not disprove climate change is happening.
“We do not just have climate change. We have the daily weather. It is summer in the southern hemisphere right now. So, we do expect to see high temperatures. It is winter in the northern hemisphere. We expect to see cold temperatures. But, in the southern hemisphere, we have seen extreme heat. A lot of records broken,” she said.
Nullis added that every single heat wave cannot be attributed to climate change. But she noted that extreme heat is one symptom of climate change. It is one of the phenomena expected from a changing climate.