1992 – 2022

Global mean sea level has risen 101 millimeters (3.98 inches) since 1992, and it continues to do so at 3.9 mm (0.15 inches) per year.

A new satellite was launched by scientists and engineers thirty years ago to examine how the waters rise and decrease over time, a job that was previously only possible from the coast. On August 10, 1992, TOPEX/Poseidon launched into orbit and began a 30-year record of ocean surface height all across the globe. The findings have verified what scientists had previously seen from the shorelines: the seas are rising, and the rate is accelerating.


Researchers have found that global mean sea level—shown in the line plot above and below—has risen 10.1 centimeters (3.98 inches) since 1992. Over the past 140 years, satellites and tide gauges together show that global sea level has risen 21 to 24 centimeters (8 to 9 inches).

Beginning with TOPEX/Poseidon, NASA and partner space agencies have flown a continuous series of satellites that use radar altimeters to monitor ocean surface topography. Essentially, the satellites monitor the vertical shape and height of the ocean. Radar altimeters continually emit pulses of radio waves (microwaves), which are reflected back toward the satellite by the ocean’s surface. The instruments calculate the time it takes for the signal to return, while also tracking the precise location of the satellite in space. From this, scientists can calculate the height of the sea surface directly underneath the satellite.

Since 1992, five missions with similar altimeters have repeated the same orbit every 10 days: TOPEX/Poseidon (1992 to 2006), Jason-1 (2001 to 2013), the Ocean Surface Topography Mission/Jason-2 (2008 to 2019), Jason-3 (2016 to present), and Sentinel-6 Michael Freilich (2020 to present). The missions were built through various partnerships between NASA, France’s Centre National d’Etudes Spatiales (CNES), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the European Space Agency (ESA), and the U.S. National Oceanic and Atmospheric Administration (NOAA).


Combined, the mission teams have assembled a unified, standardized ocean topography record that is equivalent to the work of a half-million tide gauges. The researchers accumulated and corroborated a data record that is now long enough and sensitive enough to detect global and regional sea level changes beyond the seasonal, yearly, and decadal cycles that naturally occur.

“With 30 years of data, we can finally see what a huge impact we have on the Earth’s climate,” said Josh Willis, an oceanographer at the Jet Propulsion Laboratory (JPL) and NASA’s project scientist for Sentinel-6 Michael Freilich. “The rise of sea level caused by human interference with the climate now dwarfs the natural cycles. And it is happening faster and faster every decade.”

The map at the top of this page shows global trends in sea level as observed from 1993 to 2022 by TOPEX/Poseidon, the three Jason missions, and Sentinel-6 Michael Freilich. Note the spatial variations in the rate of sea level rise, with some parts of the ocean rising faster (depicted in red and deep orange) than the global rate. Many of the anomalies reflect long-term shifts in ocean currents and heat distribution.

1992 – 2022

The altimetry data also show that the rate of sea level rise is accelerating. Over the course of the 20th century, global mean sea level rose at about 1.5 millimeters (0.06 inches) per year. By the early 1990s, it was about 2.5 mm (0.1 inches) per year. Over the past decade, the rate has increased to 3.9 mm (0.15 inches) per year.

In the line plot, the highs and lows each year are caused by the exchange of water between the land and sea. “Winter rain and snowfall in the northern hemisphere shifts water from ocean to land, and it takes some time for this to runoff back into the oceans,” Willis noted. “This effect usually causes about 1 centimeter of rise and fall each year, with a bit more or less during El Niño and La Niña years. It’s literally like the heartbeat of the planet.”

While a few millimeters of sea level rise per year may seem small, scientists estimate that every 2.5 centimeters (1 inch) of sea level rise translates into 2.5 meters (8.5 feet) of beachfront lost along the average coast. It also means that high tides and storm surges can rise even higher, bringing more coastal flooding, even on sunny days. In a report issued in February 2022, U.S. scientists concluded that by 2050 sea level along U.S. coastlines could rise between 25 to 30 centimeters (10 to 12 inches) above today’s levels.

“What stands out from the satellite altimetry record is that the rise over 30 years is about ten times bigger than the natural exchange of water between ocean and land in a year,” Willis said. “In other words, the human-caused rise in global sea level is now ten times bigger than the natural cycles.”

NASA Earth Observatory video and image by Joshua Stevens, using TOPEX/Poseidon data courtesy of Josh Willis/JPL-Caltech.

High-Intensity-Interval-Training increases fat burning more than aerobic exercise. In fact, a few sessions of HIIT per week will turn your body into a fat-burning “machine.”

High-Intensity Interval Training Can Help Burn More Fat

“If that stubborn body fat isn’t going away, consider adding High-Intensity-Interval-Training or HIIT to your exercise routine,” says Professor Zeljko Pedisic.

HIIT increases fat burning more than aerobic exercise, finds a study that was recently published in the British Journal of Sports Medicine.

How was the study conducted?

For the study, researchers pooled results from 18 controlled intervention trials on the effects of HIIT on the rate of fat burning during exercise.

The intervention trials included a total of 511 adult participants who were engaged in either supervised HIIT, moderate-intensity aerobic exercise, or a non-exercising control group.

The duration of exercise interventions ranged from 2 to 14 weeks. In almost all of the studies, participants engaged in three HIIT sessions per week.

What are the key findings?

According to the research, a few sessions of HIIT per week will turn your body into a fat-burning “machine.” HIIT will make you start burning more fat not just during the HIIT sessions, but also during other types of physical activity, such as brisk walking, swimming, and playing sports.

Fat metabolism will improve after only four weeks of HIIT, and it will continue to improve over time.

After 12 weeks of HIIT, each minute of physical activity can be expected to burn an additional 0.13 grams of fat. For someone who engages in 150 minutes of physical activity per week, this could lead to around 10 kg (22 pounds) of additional fat burned in a decade.

According to the findings, overweight individuals may expect greater increases in fat burning, compared with “normal”-weight individuals.


While people could also improve their fat metabolism by engaging in aerobic exercise (e.g. jogging), this would require a much higher time commitment, and the improvements would be smaller.

Why is this important?

These findings may help more than two billion overweight people in the world to improve their fat metabolism and reduce weight.

They may also help billions of others to prevent unwanted weight gain over time.

Picture your 10-year older self with additional 22 pounds of body fat: HIIT may help you avoid such a change in the body composition.

“According to the recent Worldwide Survey of Fitness Trends, HIIT is among the most popular types of workouts. If you are not already doing it, maybe you should give it a go,” concludes Professor Pedisic.


Reference: “Effects of high-intensity interval training (HIIT) and sprint interval training (SIT) on fat oxidation during exercise: a systematic review and meta-analysis” by Muhammed M Atakan, Yasemin Guzel, Nipun Shrestha, Sukran N Kosar, Jozo Grgic, Todd A Astorino, Huseyin H Turnagol and Zeljko Pedisic, 20 July 2022, British Journal of Sports Medicine.
DOI: 10.1136/bjsports-2021-105181

Copernicus Sentinel-2 satellite images show the stark difference between August 2021 and August 2022 on the Rhine River near Cologne.

Water levels on the Rhine River, Europe’s second-largest river, have continued to due to soaring temperatures and lack of rainfall. The low water levels are preventing many vessels from navigating through the waters at full capacity. The Copernicus Sentinel-2 mission captured satellite images of part of the Rhine River near Cologne. They show the stark difference between August 2021 and August 2022.

Flowing from the Swiss Alps to the North Sea, the Rhine River is an important shipping route for many products from grains to chemicals to coal. When water levels drop, cargo vessels need to sail with reduced load, so they don’t run aground.

Rhine River on August 25, 2021. Credit: Contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

Water levels at the chokepoint of Kaub, near Frankfurt, fell to 32 cm (13 inches) in depth on Monday, down from 42 cm (17 inches) last week. Ships, however, need around 1.5 m (5 feet) to be able to sail fully loaded. This means that current levels are making it difficult for larger ships to navigate through the waters. Freight ships continue to sail, but only with around 25% to 35% of the ship’s capacity.

The low water levels are emerging earlier than usual, with the lowest water levels typically recorded in September or October. However, reduced temperatures and predicted rainfall forecasted for this week may offer much-needed relief to the Rhine.

Rhine River on August 12, 2022. Credit: Contains modified Copernicus Sentinel data (2022), processed by ESA, CC BY-SA 3.0 IGO

The phenomenon facing the Rhine is common across much of Europe after an unusually hot and dry summer, which caused wildfires and water shortages.

The Copernicus Sentinel-2 satellites capture high-resolution imagery that provide information about the conditions on Earth, such as plant life, soil, and coastal areas. The mission consists of two satellites both of which carry an innovative multispectral imager – a camera that captures optical images over a range of wavelengths beyond visible light.

A scanning electron microscopy image of a Kamptozoa, a small aquatic invertebrate. Credit: Dr. Natalia Shunatova. Credit: Dr. Natalia Shunatova

Research suggests that the Kamptozoa and Bryozoa phyla split sooner than previously believed.

Kamptozoa and Bryozoa are two phyla of small aquatic invertebrates. They are related to snails and clams (mollusks), bristle worms, earthworms, and leeches (annelids), as well as ribbon worms (nemertea). Evolutionary biologists have long been baffled by their exact place on the tree of life and how closely linked these other species are to them. Previous research regularly shifted their place around.

Furthermore, despite the fact that Kamptozoa and Bryozoa were once thought to belong in one group, they were later separated due to their appearance and anatomy. Now, researchers from the Okinawa Institute of Science and Technology Graduate University (OIST), working with associates from St. Petersburg University and Tsukuba University, have demonstrated that the two phyla split from mollusks and worms earlier than previous studies had suggested, and thus they do in fact form a distinct group. This discovery was made possible by the use of cutting-edge sequencing technology and powerful computational analysis.


“We’ve shown that by using high-quality transcriptomic data we can answer a long-standing question to the best of our current techniques,” said Dr. Konstantin Khalturin, Staff Scientist in OIST’s Marine Genomics Unit and first author of the paper published in Science Advances.

Dr. Konstantin Khalturin and Professor Nori Satoh are two of the researchers involved in this study. Credit: OIST

A genome is the full set of genetic information found in every cell. It is subdivided into genes. These genes are made up of DNA base pairs and each gene contains the instructions needed to create a protein and thus leads to the proper care and maintenance of a cell. For the instructions to be carried out, the DNA must first be transcribed into RNA. A transcriptome is the result of this, like the reflection of a genome but written in RNA base pairs rather than DNA.


This genetic information differs among species. Those who are closely related have very similar genetic information, while a greater evolutionary distance results in more genetic differences. By using this data, researchers have improved our knowledge of animal evolution, but some questions still prove difficult to answer.

As Kamptozoa and Bryozoa are closely related to mollusks, annelids, and nemertea, small mistakes in the dataset, or missing data, can result in an incorrect placement on the evolutionary tree. Furthermore, while collecting these tiny animals, it’s easy to pick up other organisms, such as algae, that contaminate the sample. Dr. Khalturin highlighted that they were careful to avoid contamination and later screened their dataset for RNA of algae and small animals to remove any that might have come from them.

The evolutionary relationships of Kamptozoa and Bryozoa and their place on the tree of life have been revealed in this new study. The study found that they split from mollusks and worms earlier than expected and that they are part of a distinct group, called Polyzo. Credit: OIST

In total, the researchers sequenced the transcriptome of four species of Kamptozoa and two species of Bryozoa, but to a far higher quality level than had previously been achieved. While past datasets had completeness of 20-60%, in this study, the transcriptome completeness was over 96%.


Using these transcriptomes, they predicted proteins and compared them to similar data of 31 other species, some of which were closely related to Kamptozoa and Bryozoa, such as clams and bristle worms, and others that were more distant, such as frogs, starfish, insects, and jellyfish. The high-quality datasets meant that they could compare many different genes and proteins simultaneously. Dr. Khalturin credited the powerful computational capabilities that the researchers could access at OIST.

“Our main finding is that the two phyla belong together,” said Dr. Khalturin. “This result was originally proposed in the 19th century by biologists who were grouping animals based on what they looked like.”

While Dr. Khalturin stated that this question had now been answered to the best ability available, he also highlighted that the dataset could answer other fundamental evolutionary questions—such as the more precise location of mollusks and annelids on the tree of life, and how life diversified.

Reference: “Polyzoa is back: The effect of complete gene sets on the placement of Ectoprocta and Entoproc” by Konstantin Khalturin, Natalia Shunatova, Sergei Shchenkov, Yasunori Sasakura, Mayumi Kawamitsu and Noriyuki Satoh, 1 July 2022, Science Advances.
DOI: 10.1126/sciadv.abo4400