Climate change reduces warming potential of nitrous oxide by an enhanced Brewer‐Dobson circulation

Abstract

The Brewer‐Dobson circulation (BDC), which is an important driver of the stratosphere‐troposphere exchange, is expected to accelerate with climate change. One particular consequence of this acceleration is the enhanced transport of nitrous oxide (N2O) from its sources at the Earth's surface toward its main sink region in the stratosphere, thus inducing a reduction in its lifetime. N2O is a potent greenhouse gas and the most relevant currently emitted ozone‐depleting substance. Here we examine the implications of a reduced N2O lifetime in the context of climate change. We find a decrease in its global warming potential (GWP) and, due to a decline in the atmospheric N2O burden, also a reduction in its total radiative forcing. From the idealized transient global warming simulation we can identify linear regressions for N2O sink, lifetime, and GWP with temperature rise. Our findings are thus not restricted to a particular scenario.

Dynamically controlled ozone decline in the tropical mid-stratosphere observed by SCIAMACHY

“…While accelerated tropical upwelling enhances transport of N 2 O from its source towards the stratosphere, it reduces its lifetime (e.g. Kracher et al, 2016). The amount of NO x is then affected by a shorter N 2 O residence time causing its lower production via Reaction (R8a), and as a consequence less O 3 loss in the tropical mid-stratosphere.…”

Dynamically controlled ozone decline in the tropical mid-stratosphere observed by SCIAMACHY

“…(2010) and Kracher et al (2016) showed that the accelerated upwelling decreases the residence time of N 2 O in the stratosphere causing lower NO x production and as a consequence lower O 3 loss. For conditions of slower upwelling, the residence time of N 2 O in the stratosphere is expected to be longer, which then causes higher NO x production and higher O 3 loss.…”

Impact of Energetic Electron Precipitation on the Upper Atmosphere: Nitric Monoxide

“…However, its role in the global change remains unclear. It has been suggested that the upper atmospheric circulation favors the stratosphere-troposphere exchange in link with climate change through the greenhouse gas N 2 O [30]. In parallel, chemical reactions implying NO in the atmosphere produce a significant production of various nitrous oxide (see The Physical Science Basis.…”

“…NO can also be excited into 22 states, see Table (1). The corresponding cross sections come [13] for incident electron energies of 10,20,30,40 and 50 eV, and we performed a logarithmic extrapolation for larger energies. The TRANSSOLO code uses a multi-stream approach [14 -16], which solves the Boltzmann equation for electron transport in the atmosphere.…”