April 2025:
Neue Ver枚ffentlichung:
Christian Baatz, Lukas Tank, Lena-Katharina Bednarz, Miranda Boettcher, Teresa Maria Morganti, Lieske Voget- Kleschin, Tony Cabus, Erik van Doorn, Tabea Dorndorf, Felix Havermann, Wanda Holzh眉ter, David Peter Keller, Matthias Kreuzburg, Nele Matz-L眉ck, Nadine Mengis, Christine Merk, Yiannis Moustakis, Julia Pongratz, Hendrikje Wehnert, Wanxuan Yao and Gregor Rehder (2025): "A holistic assessment framework for marine carbon dioxide removal options." Environmental Research Letters,
Abstract:
Marine Carbon Dioxide Removal (mCDR) options could potentially play an important role in future CDR policy portfolios. They include, for example, ocean alkalinity enhancement, blue carbon projects such as mangrove cultivation, as well as sub-seabed storage of captured atmospheric CO2. We present a novel assessment framework designed for mCDR options. The framework provides important conceptual advancements to existing frameworks currently used to assess climate options: It clearly distinguishes between and allows for the assessment of both the feasibility and desirability of mCDR options, it makes explicit the evaluative standards upon which the assessment is based and it separates the descriptive listing of information from the evaluation of said information. The assessment framework aims to advance the debate on what role mCDR can and should play in responding to the climate crisis by providing a tool for both policymakers and stakeholders to assess mCDR options in a transparent and comprehensive way.
April 2025:
Neue Ver枚ffentlichung:
Tank, L., Voget-Kleschin, L., Garschagen, M., Boettcher, M., Mengis, N., Holland-Cunz, A., Rehder, G., and Baatz, C. (2025) "Distinguish between feasibility and desirability when assessing climate response options." npj Climate Action 4, 34.
Abstract:
The current literature on assessing climate change response options does not sufficiently distinguish between assessing options in terms of their feasibility and in terms of their desirability. One example of this is the IPCC feasibility assessment framework. We argue that assessments of climate response options should indeed cover questions of desirability, but they should do so explicitly. Transparency about underlying normative standards is the key to a productive desirability assessment.
M盲rz 2025:
Neue Ver枚ffentlichung:
Huo, W., Spiegl, T., Wahl, S., Matthes, K., Langematz, U., Pohlmann, H., Kr枚ger, J. (2025) "Assessment of the 11-year solar cycle signals in the middle atmosphere during boreal winter with multiple-model ensemble simulations." Atmospheric Chemistry and Physics, 25 (4), 2589鈥�2612,
Summary:
To better understand possible reasons for the diverse modeling results and large discrepancies of the detected solar fingerprints, we took one step back and assessed the 鈥渋nitial鈥� solar signals in the middle atmosphere based on a set of ensemble historical simulations with multiple climate models 鈥� the Flexible Ocean Climate Infrastructure (FOCI), the ECHAM/MESSy Atmospheric Chemistry (EMAC), and the Max Planck Institute for Meteorology Earth System Model in high-resolution configuration (MPI-ESM-HR). Consistent with previous work, we find that the 11-year solar cycle signals in the shortwave heating rate (SWHR) and ozone anomalies are robust and statistically significant in all three models. These initial solar cycle signals in the SWHR, ozone, and temperature anomalies are sensitive to the strength of the solar forcing. Correlation coefficients of the solar cycle with the SWHR, ozone, and temperature anomalies linearly increase along with the enhancement of the solar cycle amplitude. This reliance becomes more complex when the solar cycle amplitude 鈥� indicated by the standard deviation of the December鈥揓anuary鈥揊ebruary mean F10.7 鈥� is larger than 40. In addition, the cold bias in the tropical stratopause of EMAC dampens the subsequent results of the initial solar signal. The warm pole bias in MPI-ESM-HR leads to a weak polar night jet (PNJ), which may limit the top-down propagation of the initial solar signal. Although FOCI simulated a so-called top-down response as revealed in previous studies in a period with large solar cycle amplitudes, its warm bias in the tropical upper stratosphere results in a positive bias in PNJ and can lead to a 鈥渞eversed鈥� response in some extreme cases. We suggest a careful interpretation of the single model result and further re-examination of the solar signal based on more climate models.
Initial 11-year solar cycle signals in the upper and middle stratosphere vs. the solar cycle amplitude. (a) Scatter plot of correlation coefficients between the annual shortwave heating rate anomalies in the tropical stratopause (averaged over 25掳鈥塖鈥�25掳鈥塏 at 1鈥塰Pa) and the annual F10.7 index in all 45-year running windows vs. the solar cycle amplitude (standard deviations of the annual F10.7 index in all 45-year windows) for FOCI (ensemble mean: black; light gray: individual members) and EMAC (brown: ensemble mean; light brown: individual members) in the FULL experiment. The dashed black line indicates the 95鈥�% significance level. Panel (b) is the same as (a) but for the temperature anomalies at 1鈥塰Pa from FOCI, EMAC, and MPI-ESM-HR (blue: ensemble mean; light blue: individual members). Panel (c) is the same as (a) but for the O3 volume mixing ratio anomalies at 10鈥塰Pa from FOCI and EMAC.
M盲rz 2025:
M207 cruise:
M207 expedition on the RV METEOR took a place from January 4 to February 11, 2025, from Belem, Brazil to Mindelo, Cabo Verde.
The EXPORT is the part of the WARD Tropics expedition, which focused on the trans-Atlantic transport of mineral dust. With this aim the new portable meteorological observatory for desert-dust transport was installed on board of the ship. Dust particles can affect climate in many different ways, from affecting radiative forcing to playing a role of nutrient supplier. During the expedition we had an opportunity to measure the Saharan dust, transported far away from the source along tropical Atlantic. Several instruments were installed on board of METEOR, like ceilometer, particle flat plate, active volume sampler, disdrometer, solar radiation measurement station and also different sun photometers to record the aerosol optical depth were used.
