Zählt irgendjemand das freigesetzte CO2 aus Waldbränden?

Jahrelang ging es in Deutschland mit dem Absatz von Solaranlagen steil aufwärts. Doch jetzt melden zwei Drittel der Solarinstallateure in einer Umfrage des Branchenmagazins “pv magazine” für die vergangenen Monate einen Einbruch bei ihrem Geschäftsgang. Sind das Anzeichen einer Trendwende? Alex Reichmuth ist der Sache im Nebelspalter (https://www.nebelspalter.ch/themen/2024/04/nachfrage-nach-solaranlagen-in-deutschland-geht-rasant-zurueck) nachgegangen.

Nachfrage nach Solaranlagen in Deutschland geht rasant zurück

Die Fakten: Zwei Drittel der deutschen Solarinstallateure melden für die letzten Monate einen Einbruch beim Absatz von Photovoltaikanlagen.

Warum das wichtig ist: Jahrelang ist es mit den Absatzzahlen steil bergauf gegangen. Der Rückschlag, den die PV-Installateure in der zweiten Hälfte von 2023 verzeichnen mussten, könnte ein Anzeichen sein, dass die Solarbäume eben doch nicht in den Himmel wachsen. Das muss auch die Solarbranche in der Schweiz beunruhigen.

Die ganze Story gibt es im Nebelspalter (https://www.nebelspalter.ch/themen/2024/04/nachfrage-nach-solaranlagen-in-deutschland-geht-rasant-zurueck). Der Artikel kann nach 20 Sekunden Werbung freigeschaltet werden.


Ryan Katz-Rosene auf The Conversation:

If a tree burns in Canada’s unmanaged forest, does anyone count the carbon?

Earlier this fall, a commentary in the journal Nature Communications, Earth & Environment argued for a change to the implementation of the Paris Agreement’s reporting mechanisms. The authors called for all countries to report carbon emissions and removals taking place across their entire territories, not just within so-called “managed” lands (as is presently the case).

However, this poses a challenge here in Canada, as there is deep uncertainty about the total carbon flux (balance of emissions and captures) in Canada’s “unmanaged” land.

I echo calls for the Government of Canada to scale up and improve its greenhouse gas (GHG) monitoring and modelling across Canada’s entire territory, and to report these findings in a much more open and transparent manner as part of its annual National GHG Inventory.

Differentiating between managed and unmanaged land

Under the UN Framework Convention on Climate Change, member countries are expected to report GHG emissions and removals taking place as a result of human activities. However, within the LULUCF (or Land Use, Land-Use Change, and Forestry) sector, it is not always clear what constitutes an anthropogenic influence.

The guidance provided by the Intergovernmental Panel on Climate Change (IPCC) has been to delineate between “managed” and “unmanaged” lands, and to focus GHG reporting on the former since these are areas under substantive human influence. While a number of countries make use of this distinction, the portion of land in Canada that is unmanaged is truly significant — equivalent to about 69 per cent of the country’s total land area.

Canada’s National GHG Inventory does contain information about the carbon flux within managed lands, or lands comprised mostly of managed forest. There is currently around 232 million hectares of managed forest in Canada, however, this leaves roughly 715 million hectares of land in Canada which is technically unmanaged — all of which are unaccounted for in the National GHG Inventory.

What’s more, while Canada does track emissions from natural disturbances (such as in a forest fire) occurring in managed areas, it does not actually report these disturbances to the UN as part of its LULUCF emissions, based on the claim that these are not anthropogenic.

While there is a logic to separating these out, there is a substantial difference to Canada’s total LULUCF emissions, depending on whether or not they are included. For instance, if natural disturbances are included in the tally, Canada’s managed land is typically a net source of carbon, while if they are not included, Canada’s managed land is typically a net carbon sink.

The underlying problem, however, is the lack of clear and transparent information about GHG emissions and removals in Canada’s unmanaged lands.

Estimates vary widely

Earlier this summer, during Canada’s unprecedented wildfire season, I asked the Ministry of Energy and Natural Resources of Canada (NRCAN) for historical information about the net Carbon flux in unmanaged lands. I was surprised to learn that NRCAN does not yet have this data.

What NRCAN does have is a very robust carbon budget modelling tool, and thanks to this, some preliminary (unverified) estimates of wildfire emissions in unmanaged forests.

Wildfire emissions estimates for unmanaged forests are indeed a step in the right direction (as wildfires account for the bulk of emissions from natural disturbances), but there still remains a majority of unmanaged land which is not forested — including, for instance, vast peatlands which are also subject to wildfires.

No GHG emissions of any type occurring in unmanaged lands are currently being tracked or reported within the National GHG Inventory process.

There have been various efforts to quantify these emissions, yet estimates vary considerably, with some data sets limited to forest lands, and others looking at the full national territory.

One recent estimate used 16 different “Dynamic Global Vegetation Models,” and found that over the 20-year period from 2000-2020 unmanaged forests sequestered on average about 189 Megaton CO2 per year.

However, the Global Carbon Project’s estimates of “atmospheric inversions” suggests there may be orders of magnitude more carbon removal in Canada’s unmanaged land.

The size of the discrepancy between these estimates is puzzling. While one obvious explanation comes down to the former model using intact forests as a proxy for unmanaged land, and the latter model including all of Canada’s unmanaged land area, scientists believe there may be more to this discrepancy.

A need for further research and better reporting

It is unfortunate that Canada has no publicly stated estimate of the country’s total carbon flux. This is important information to help track whether Canada’s landmass is sequestering enough CO2 to offset natural disturbances, or whether the latter are outweighing the former.

It is essential that the Government of Canada enhance its current efforts in land-based carbon flux analysis, and that such data and analysis is reported to the public in a more clear and transparent way.


Zhang Nannan, Chinese Academy of Sciences:

Researchers reveal linkage between wildfire activity and abrupt climate events during the Holocene

As a major Earth system component, wildfire plays an important role in the Earth’s terrestrial ecosystems and climate system, with significant impacts on the atmosphere, radiation effects, vegetation, surface properties, global biogeochemical cycles and human survival. Understanding the interactions among wildfires, climate change, vegetation, and human activities over geologic time is a viable approach to making accurate projections of future wildfire occurrences, which is crucial for human adaptation to possible wildfire threats.

A research group led by Prof. Han Yongming from the Institute of Earth Environment of the Chinese Academy of Sciences reconstructed a high-resolution wildfire history of the monsoon marginal zone in the Holocene by using soot records from Qinghai Lake sediments, to explore the relationship between wildfire and its possible driving factors.

They found that on the sub-orbital timescale, fewer wildfires occurred during the early-middle Holocene under humid climate. With the weakened monsoon and increased aridification during the mid- to late Holocene, wildfires increased and remained at high levels since 3.0 cal ka before present.

On a millennial timescale, there were extremely severe wildfire periods that were centered around ca. 1.6, 2.5, 4.1, 4.9, 6.3, 7.8, 9.6, 10.5 and 11.4 cal ka before present, respectively, which were strongly correlated with millennial timescale abrupt weak monsoon events.

By comparing the soot records, climate proxies and possible driving factors, they also found that on both suborbital and millennial timescales, drought climate associated with a weakened monsoon, which was likely modulated by solar radiation (activity), may be the major factor driving the rapid increase in wildfires in the Holocene.

In general, temperature is thought to drive wildfire activity, with high temperatures being favorable for wildfire occurrence. However, this work suggests that the rapid increase in wildfires is closely related to abrupt dry/cold climate events on a millennial timescale.

This work, published in Quaternary Science Reviews, may provide a new insight for fire prediction, especially for those extreme wildfires that often feed back to abrupt coal/dry climate events in monsoon-dominated regions.

Yifei Hao et al, Holocene wildfire on the Qinghai-Tibetan Plateau–witness of abrupt millennial timescale climate events, Quaternary Science Reviews (2023). DOI: 10.1016/j.quascirev.2023.108373


University of Rochester:

Scientists uncover link between ocean weather and global climate, using mechanical rather than statistical analysis

An international team of scientists has found the first direct evidence linking seemingly random weather systems in the ocean with climate on a global scale. Led by Hussein Aluie, an associate professor in the University of Rochester’s Department of Mechanical Engineering and staff scientist at the University’s Laboratory for Laser Energetics, the team reported their findings in Science Advances.

The ocean has weather patterns like what we experience on land, but on different time and length scales, says lead author Benjamin Storer, a research associate in Aluie’s Turbulence and Complex Flow Group. A weather pattern on land might last a few days and be about 500 kilometers wide, while oceanic weather patterns such as swirling eddies last three to four weeks but are about one-fifth the size.

“Scientists have long speculated that these ubiquitous and seemingly random motions in the ocean communicate with climate scales, but it has always been vague because it wasn’t clear how to disentangle this complex system to measure their interactions,” says Aluie. “We developed a framework that can do exactly that. What we found was not what people were expecting because it requires the mediation of the atmosphere.”

The group’s goal was to understand how energy passes through different channels in the ocean throughout the planet. They used a mathematical method developed by Aluie in 2019, which was subsequently implemented into an advanced code by Storer and Aluie, that allowed them to study energy transfer across different patterns ranging from the circumference of the globe down to 10 kilometers. These techniques were then applied to ocean datasets from an advanced climate model and from satellite observations.

The study revealed that ocean weather systems are both energized and weakened when interacting with climate scales, and in a pattern that mirrors the global atmospheric circulation. The researchers also found that an atmospheric band near the equator called the “intertropical convergence zone,” which produces 30% of global precipitation, causes an intense amount of energy transfer, and produces ocean turbulence.

Storer and Aluie say that studying such complex fluid motion happening at multiple scales is not easy, but that it has advantages over previous attempts to link weather to climate change. They believe the team’s work creates a promising framework for better understanding the climate system.

“There’s a lot of interest in how global warming and our changing climate is influencing extreme weather events,” says Aluie. “Usually, such research efforts are based on statistical analysis that requires expansive data to have confidence in the uncertainties. We are taking a different approach based on mechanistic analysis, which alleviates some of these requirements and allows us to understand cause and effect more easily.”

The team that played a central role in the investigation also included Michele Buzzicotti, a research scientist at the University of Rome Tor Vergata; Hemant Khatri, a research associate at the University of Liverpool, and Stephen Griffies, a senior scientist at Princeton.

Paper: Benjamin Storer et al, Global Cascade of Kinetic Energy in the Ocean and the Atmospheric Imprint, Science Advances (2023). DOI: 10.1126/sciadv.adi7420www.science.org/doi/10.1126/sciadv.adi7420