Climate Change Review: 2020

Introduction

• 2020 was marked by significant climate events despite ongoing global challenges, including COVID-19.
• It was either the hottest or joint-hottest year on record, according to global temperature datasets.

Global Temperature Records

• Surface temperature is the key metric often reported in climate discussions.
• 2020 was declared the hottest year by NASA, while other datasets ranked it closely behind 2016.
• Minor differences in temperature (less than 0.05 degrees) result in these discrepancies.

Context of 2016 vs. 2020

• 2016 had a significant El Niño event, boosting its surface temperatures.
• Despite lacking this boost, 2020 matched 2016's temperatures, indicating rising global heat levels.

Ocean Heat Content

• Over 90% of recent warming has occurred in the oceans.
• 2020 was the hottest year recorded for ocean heat content, with 2016 ranking sixth.

Long-Term Warming Trends

• Every decade since the 1980s has been progressively hotter.
• Last year below the 1951-1980 average was 1976.
• Climate change skepticism persists, often based on selective data interpretation.

Impact on Climate Events in 2020

• Massive wildfires occurred in Australia, the US West Coast, the Amazon, and Siberia.
• Siberia experienced significantly higher temperatures than usual.
• The Arctic saw its second-lowest sea ice coverage in history.

Predictions and Trends

• Past predictions by climate scientists have been highly accurate regarding warming and ice loss.
• The IPCC AR5 report highlighted intensified wildfires as a key climate risk.

Future Climate Outlook

• Without significant action, rising CO2 will continue warming the planet.
• 2020's warmth may become average without achieving carbon neutrality.

Effects of COVID-19 on Emissions

• 2020 saw a 7% drop in global CO2 emissions due to pandemic lockdowns.
• Despite reductions, CO2 levels remain high and continue to rise.
• Renewable energy surpassed coal in the US in 2020.

Opportunities and Challenges

• COVID-19 presents an opportunity to maintain emissions reductions and combat climate change.
• Historical emissions reductions (e.g., post-2008) quickly rebounded.

Conclusions and Lessons from 2020

• 2020 highlighted global societal and economic fragility.
• It emphasized the importance of decisive climate action and science.
• Ultimately, 2020 serves as a warning and an opportunity for better future climate policies.