Radiocarbon monoxide indicates increasing atmospheric oxidizing capacity.

Hydroxyl (OH) is the atmosphere's main oxidant removing most pollutants including methane. Its short lifetime prevents large-scale direct observational quantification. Abundances inferred using anthropogenic trace gas measurements and models yield conflicting trend estimates.

Investigations on 5,6,7,8-tetrahydro-[1,2,4]triazolo[1,2-]pyridazin-1-amines and related compounds: synthesis, chemical behaviour, structure elucidation and iNOS inhibitory activity.

The present work reports on the preparation of the hitherto unknown title compounds with various synthetic routes described. The initially pursued concept of S-N exchange with varioius 1-substituted 3-methylsulfanyl-5,6,7,8-tetrahydro-1 -[1,2,4]triazolo[1,2- ]pyridazines by using nitrogen nucleophiles was only marginally successful. The reactions proceeded slowly and the yields were low, mainly because of the pronounced formation of 5,6,7,8-tetrahydro-[1,2,4]triazolo[1,2- ]pyridazin-1-imines by oxidation of the heterocyclic amines initially formed.

Stratospheric water vapor affecting atmospheric circulation.

Water vapor plays an important role in many aspects of the climate system, by affecting radiation, cloud formation, atmospheric chemistry and dynamics. Even the low stratospheric water vapor content provides an important climate feedback, but current climate models show a substantial moist bias in the lowermost stratosphere. Here we report crucial sensitivity of the atmospheric circulation in the stratosphere and troposphere to the abundance of water vapor in the lowermost stratosphere.

The Montreal Protocol protects the terrestrial carbon sink.

The control of the production of ozone-depleting substances through the Montreal Protocol means that the stratospheric ozone layer is recovering and that consequent increases in harmful surface ultraviolet radiation are being avoided. The Montreal Protocol has co-benefits for climate change mitigation, because ozone-depleting substances are potent greenhouse gases. The avoided ultraviolet radiation and climate change also have co-benefits for plants and their capacity to store carbon through photosynthesis, but this has not previously been investigated.

Large impacts, past and future, of ozone-depleting substances on Brewer-Dobson circulation trends: A multi-model assessment.

Substantial increases in the atmospheric concentration of well-mixed greenhouse gases (notably CO), such as those projected to occur by the end of the 21st century under large radiative forcing scenarios, have long been known to cause an acceleration of the Brewer-Dobson circulation (BDC) in climate models. More recently, however, several single-model studies have proposed that ozone-depleting substances might also be important drivers of BDC trends. As these studies were conducted with different forcings over different periods, it is difficult to combine them to obtain a robust quantitative picture of the relative importance of ozone-depleting substances as drivers of BDC trends.