Evidence of human hand in climate change found in upper stratosphere

How groundwater pumping has changed the earth’s tilt, a global network to share pathogen genomics data, and more in this edition of Science Notebook.

The probe is designed for specific detection of acetylcholinesterase, a crucial enzyme that hydrolyses the neurotransmitter acetylcholine and is linked to Alzheimer’s progression. | Photo Credit:  Tabish Iqbal

New research has provided the clearest evidence of a human “fingerprint” on climate change and shows that specific signals from human activities have altered the temperature structure of the earth’s atmosphere.

Differences between tropospheric and lower stratospheric temperature trends have long been recognised as a fingerprint of human effects on climate. This fingerprint, however, neglected information from the mid to upper stratosphere, 25-50 km above the earth’s surface.

Including this information improves the detectability of anthropogenic effects by a factor of five. “Enhanced detectability occurs because the mid to upper stratosphere has a large cooling signal from human-caused CO2 increases, small noise levels of natural internal variability, and differing signal and noise patterns,” according to the research paper published in a recent issue of the Proceedings of the National Academy of Sciences by an international research team led by the Woods Hole Oceanographic Institute, Massachusetts, USA.

According to the research, noise in the troposphere can include day-to-day weather, inter-annual variability arising from El Niños and La Niñas, and longer-term natural fluctuations in climate. In the upper stratosphere, however, the noise of variability is smaller, and the human-induced climate change signal is larger.

Groundwater pumping has changed the earth’s tilt

The shifting of mass and the consequent sea-level rise due to massive groundwater withdrawal has caused the earth’s rotational pole to shift by nearly a metre in two decades, according to a new study published in Geophysical Research Letters.

Humans have pumped such huge quantities of water out of the ground and moved them elsewhere that the earth’s axis has tilted nearly 4.36 cm/year east between 1993 and 2010 alone. Based on climate models, it is estimated that, during this period, humanity pumped out 2,150 gigatonne of groundwater from natural reservoirs, which is equivalent to a global sea-level rise by about 6 mm.

The figure compares the observed polar motion (red arrow, “OBS”) to the modelling results without (dashed blue arrow) and with (solid blue arrow) groundwater mass redistribution.   | Photo Credit: Geophysical Research Letters (2023)

While the tilt of the axis on which any celestial object spins tends to be stable, small shifts can occur when large masses move inside a planet and on its surface. It has been known since 2016 that the rotational pole is affected by climate-related processes, such as the thawing of icebergs and the redistribution of the mass of the water locked in them.

But until the present study, which adds groundwater withdrawal, the results did not match observations; it was off by 78.5 cm. “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole,” said Ki-Weon Seo of Seoul National University, who led the study.

Global network to share pathogen genomics data

In May end, the World Health Organisation launched a global network based on pathogen genomics for protection from infectious disease threats. The WHO’s International Pathogen Surveillance Network (IPSN) will provide a platform to connect countries and regions, improving systems for collecting and analyzing samples, using these data as part of a broader disease surveillance system to drive public health decision-making and to develop treatments and vaccines.

Pathogen genomics analyses the genetic code of viruses, bacteria, and other disease-causing organisms to understand how infectious they are, how deadly they are, and how they spread.

A 3D rendering of a strain of SARS CoV 2. | Photo Credit: Getty Images/iStockphoto

COVID-19 highlighted the critical role pathogen genomics plays in responding to pandemic threats. Without the rapid sequencing of the SARS-COV-2 genome, vaccines would not have been as effective, or have been made available so quickly. Also, new, more transmissible variants of the virus would not have been as quickly identified.

According to Nature, a draft of a “pandemic treaty” — an agreement among countries about how to best respond to the next massive outbreak—is also in the works. But one sticking point has been how to compensate countries for sharing viral-genome sequences as the experience from COVID-19 itself had shown. “[M]any of the countries that uploaded sequences were slow to receive [vaccine] shots, if they got them at all. This disconnect sets up a situation in which disease-affected countries might one day decide to keep information to themselves,” the journal said.

Detecting Alzheimer’s early with fluorogenic probe

Scientists at the Indian Institute of Science (IISc), Bengaluru, have designed a small molecular fluorogenic probe that can sense an enzyme linked to the progression of Alzheimer’s disease. The probe, according to the IISc release, is reliable and cost-effective and can be fabricated into a strip-based kit that may enable on-site diagnosis. The currently used techniques, such as MRI, PET, and CT scans are complex, expensive, and often produce inconclusive results. The work has been published in Analytical Chemistry.

Studies have shown that in the early stages of Alzheimer’s, levels of the enzyme Acetylcholinesterase (AChE) become imbalanced, thus making it a potential biomarker for the disease. “Fluorogenic probes are not fluorescent by themselves, but upon reaction with [the] target enzyme [AChE], they become fluorescent,” says Das, one of the authors.

To test the probe’s ability to be taken in by the enzyme, the team used commercially available AChE and lab-made human brain AChE expressed in bacteria. Although AChE has been extracted from the human brain, purified, and crystallised in the past, this is the first time that it has been purified in the active form after cloning and expressing it in a bacterial system, the researchers said. The team showed that the fluorogenic probe could also enter brain cells cultured in the lab and fluoresce upon contact with AChE.

A unique SUIT for ISRO solar mission

The first solar mission of the Indian Space Research Organisation (ISRO), Aditya-L1, will carry seven different payloads capable of studying various phenomena on the sun across the electromagnetic spectrum and solar wind. The Solar Ultraviolet Imaging Telescope (SUIT) is one of them.

SUIT has been built by a team of scientists from Indian institutions and universities engaged in astronomy research under the leadership of A.N. Ramaprakash and Durgesh Tripathi of the Inter-University Centre for Astronomy and Astrophysics (IUCAA) in close collaboration with ISRO. SUIT was recently delivered to ISRO.

The solar space telescope SUIT. | Photo Credit: IUCAA

Aditya-L1 will orbit around the first Lagrange point (L1), which is 1.5 million km from the earth towards the sun. It will seamlessly measure solar radiation from hard X-ray to infrared, as well as in situ measurements of particles in the solar wind and the sun’s magnetic field at L1.

SUIT will provide full disk images of the sun in the 200-400 nanometre wavelength range. Full disk images in the entire wavelength range have never been obtained, according to an IUCAA release.

The telescope will address fundamental questions such as the existence of a higher temperature atmosphere above the cooler surface, the origin and variation of near-UV solar radiation, and high energy explosions such as solar flares. With its capabilities, SUIT will provide observations of the solar atmosphere slicing through different layers, which is currently missing.