How has the oceans changed in the last 30 years?

Large-scale study of the oceans

Pundits from the University of Melbourne will help us analyze the situation. Local scientists conducted an extensive study based on the results of observations for 30 years. This study was published relatively recently - the end of April 2022. 

The research period is quite extensive and lasted 33 years. The start of data collection fell on 1985 and ended in 2018. The study included observations of temperature, wind speed and wave height.

Scientists used data from 31 satellites orbiting our planet. Satellites continuously collected and transmitted new information. The devices were equipped with high-quality measuring instruments even today for assessing the height of waves, speed and direction of the wind - for this, altimeters, radiometers and scatterometers were used. Over 33 years of observations, the satellites managed to make more than 4 billion measurements!

Measuring the surface of the planet with the help of satellites from space is not bad, but it would be even better to have data directly from the oceans. To do this, scientists have created 80 ocean buoys. They are located all over the planet. Thus, the researchers had two global sources of data to compare. 

wind forces

One of the first conclusions made by scientists is that the strength of the winds has increased on the planet as a whole. More powerful and strong winds are recorded around the globe. Interestingly, most of them ended up in the Southern Hemisphere. It was there that an increase in the average wind speed was observed.

Naturally, you can object that the “average speed” is the average, that it takes into account the maximum and minimum values of the wind force, but in reality there are no global differences. Therefore, it is meaningless to judge the “average temperature in the ward”. Scientists took into account this factor. Therefore, for each group of winds - conditionally “weak”, “medium” and “strong” - its own statistical sample was made. 

As a result, the study showed that for 33 years the speed of conditional “strong” winds increased by 5 kilometers per hour. There are changes in the “weak” and “medium” ones, but not so much. At the same time, the number of “strong” winds in all oceans also increased. 

If we return to the indicator of the average wind speed, we will find that the average speed has increased the most in the waters of the Indian Ocean. Slightly less average speed increased in the Atlantic and Pacific. In other regions of the world, there is a trend towards an increase in the average wind speed, but so far remains insignificant.

Interestingly, no regions were found where the winds weakened. Everywhere there is either no tendency to increase or, more often, a noticeable increase in winds.

Waves and their height

It is logical that an increase in wind contributes to an increase in the unrest of the oceans of the planet. This means one thing - an increase in the height of the waves. The sharpest jump in wave height occurred in the 90s and amounted to 30 centimeters. It would seem a little, but it has its effect on nature. 

In proportion to the size of the wave, its strength increases. Accordingly, 30 centimeters on a small wave is a noticeable increase. What can we say about tsunamis or superwaves? 

Scientists from the University of Melbourne claim that the frequency of superwaves and tsunamis has increased along with their destructive power. Superwaves and rising seas are not the best mix possible. Because of this, floods occur an order of magnitude more often, the coastline changes very quickly. At the same time, dams are in danger of becoming an insufficient protection measure due to rising wave heights.

Is there a connection with climate change on the planet?

Unfortunately, it is not possible to answer this question 100%. Moreover, the results obtained cannot be directly related only to global climate change. Recall that such changes entail not only an increase in the level of the World Ocean - also increasing temperature differences, changing the stable climate in specific areas, increasing the frequency of floods, droughts and extreme heat.

However, scientists from Melbourne believe that the results of research in general can be linked to climate change. Nevertheless, scientists warn against reckless interpretations of the data obtained - an increase in wind speed is quite a common phenomenon, although the data obtained indicate some anomalous recent changes. In the South Pacific, for example, an increase in wind speed is normal over a period of 2-7 years. Then there is a drop in speed. 

At the same time, scientists state another fact - if a change in wind speed by 5% and wave height by 8% percent may look insignificant and not critical, then the upward trend in these indicators due to climate change is quite real. Moreover, such a small but constant increase in wind and wave heights will continue due to climate problems, the consequences will be serious. 

Again, at the local level within the conventional Mediterranean Sea, it is unlikely that something will change globally. But the frequency of seasonal strong and dangerous winds will increase, they will also appear outside the usual periods, and their strength will become greater. The recent hurricane in Corsica in August 2022 is a prime example of this. 

In fact, it turns out a vicious circle. The climate is changing and warming the ocean, which warms the surface of the planet. The surface of the planet gives off heat to the atmosphere, which creates stronger and more evil winds. Winds, in turn, provoke the appearance of stronger waves, and waves with wind together exacerbate existing climate problems.

Forecast…

Now scientists are planning a new global data collection and the creation of an equally global climate model. The model will be created for the next hundred years. Scientists will try to predict future climate change and how it will affect the oceans.

Moreover, such a long-term study is needed in order to be more likely to identify long-term “seasonal” changes from the real impacts of climate change. “Seasonal” is in quotation marks because these “seasons” can last up to 10-15 years. 

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09.12.2022