A comprehensive new assessment of ocean warming highlights future climate risks

Nature Reviews Earth & Environment (2022). DOI: 10.1038 / s43017-022-00345-1 “width =” 800 “height =” 462 “/>

Changes in the Earth system related to ocean warming. Credit: Reviews about nature Earth and environment (2022). DOI: 10.1038 / s43017-022-00345-1

A research study just published on Reviews about nature Earth and environment provides new insights into how warm the planet has warmed and what warming we might expect in the coming decades. This study is important because it motivates us to take action to mitigate and respond to climate change. It shows what will happen if we don’t act to slow global warming.

As humans emit greenhouse gases into the atmosphere, it causes the Earth to warm. The vast majority of the heat ends up in the ocean (over 90%). So to understand how fast the Earth’s climate is changing, we need to look to the ocean and track the change in the ocean’s heat content. The ocean provides the key to understanding both our past and our future. The warming of the oceans also links the energy, carbon and water cycles, as it is a key component of the Earth system.

This comprehensive review involved scientists from around the world and included leading institutions in China, France, the US, Australia, and the UK. The authors gathered temperature information from the world ocean using a variety of temperature sensors. Some of these temperature sensors are manually placed in the oceans by researchers, others are deployed by merchant ships, and many are self-contained devices that float in the ocean or are tied up, like a buoy or mooring. By combining many thousands of temperature measurements scattered around the world, scientists were able to piece together a clear picture of the changing global heat content of the oceans up to the 1950s.

With these measurements, the community produced many datasets to monitor ocean warming. The authors made a thorough assessment of the validity of each dataset based on progress in the field over the past few years, then were able to calculate how quickly the ocean warmed.

They found that the warming of the upper 2,000 meters began, unequivocally, at least in the 1950s. The warming has continued ever since. Now, warming oceans above 2000m are accelerating at a rate that has more than doubled (from

A second discovery is that we can predict what will happen to the ocean in the coming decades. Scientists use measurements from the past to help predict what the future will bring.

The most important discovery is: the future of the ocean is in our hands. If deep cuts in greenhouse gas emissions are made (i.e., if the Paris Agreement’s goal of limiting global surface temperature to 2 ° C above pre-industrial level), the acceleration of ocean warming will stop around to 2030. However, if we do not act, the forecasts are rather dire. The warming rate will skyrocket throughout the 21stst century: by 2090, the rate of ocean warming is projected to be four times the current level.

Another finding from the paper is that although ocean warming across all basins is expected to continue warming throughout 21st century, some ocean regions are warming faster than others. For example, the Atlantic Ocean and the Southern Oceans are warming much faster than the Pacific Ocean and the Indian Ocean.

By the end of this century, the Pacific Ocean is expected to become the largest reservoir of heat due to its large volume. The authors were able to show that when the extra heat enters the ocean, streams of water can carry that heat to the ends of the planet.

A warmer ocean has enormous consequences on Earth. Not just marine life, but also the weather conditions around the planet and the food chain. A warmer ocean leads to more intense storms, more deadly rains and floods, and more powerful typhoons and hurricanes. One consequence of warming is that parts of the planet will become drier, with more heat waves and droughts. Other parts will become wetter as rainfall occurs in larger rainfall. Coastal regions are increasingly vulnerable in association with sea level rise, storm surges and negative impacts on ecosystems. 2022 has already suffered a wide range of climate disasters: heat waves, floods, heavy rains and severe hurricanes.

Deep ocean warming with climate change

More information:
Lijing Cheng et al, Past and Future Ocean Warming, Reviews about nature Earth and environment (2022). DOI: 10.1038 / s43017-022-00345-1

Provided by the Chinese Academy of Sciences

Citation: New comprehensive assessment of ocean warming highlights future climate risks (2022, October 18) retrieved October 18, 2022 from https://phys.org/news/2022-10-comprehensive-ocean-highlights-future-climate. html

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