Here are the current Papers & Articles under the research topic Climate Change. (See also the Arctic/Antarctic heading for more papers relating to climate change). Click on the title of a paper you are interested in to go straight to the full paper.
Jet stream: Is climate change causing more ‘blocking’ weather events?
Q&A by Carbon Brief published June 2020. Extract:
Blocking events bat away oncoming low-pressure systems that would bring the prospect of clouds and rain. They are particularly synonymous with heatwaves and drought in summer and bitterly cold conditions in winter. But what are the prospects for blocking events in a warming climate? And could a rapidly warming Arctic also have a role to play? In this Q&A, Carbon Brief takes a closer look at the causes of blocking events and the potential changes in the future.
Blocking and its Response to Climate Change
2018 paper. Abstract:
Atmospheric blocking events represent some of the most high-impact weather patterns in the mid-latitudes, yet they have often been a cause for concern in future climate projections. There has been low confidence in predicted future changes in blocking, despite relatively good agreement between climate models on a decline in blocking. This is due to the lack of a comprehensive theory of blocking and a pervasive underestimation of blocking occurrence by models. This paper reviews the state of knowledge regarding blocking under climate change, with the aim of providing an overview for those working in related fields.
Impact of climate change on wintertime European atmospheric blocking
Published 1st April 2022
We study the impact of climate change on wintertime atmospheric blocking over Europe focusing on the frequency, duration, and size of blocking events. These events are identified via the weather type decomposition (WTD) methodology applied on the output of climate models of the Coupled Model Intercomparison Project phase 6 (CMIP6). Historical simulations and two future scenarios, SSP2-4.5 and SSP5-8.5, are considered. The models are evaluated against the reanalysis, and only a subset of climate models, which better represent the blocking weather regime in the recent-past climate, is considered for the analysis. We show that the spatio-temporal characteristics of recent-past atmospheric blocking are in agreement with previous studies that define blocking events with blocking indexes. We find that frequency and duration of blocking events remain relatively stationary over the 21st century. We define a methodology that relies on the WTD for the blocking event identification in order to quantify the size of the blocking events, and we find that the blocking size is basically unchanged in the future.
Barents-Kara sea ice and European winters in EC-Earth
Published 22 Feb 2020.
The potential link between decreasing Barents-Kara sea ice and cold winters in Europe is investigated using the enhanced resolution (horizontal atmospheric resolution of ∼80km) global, coupled climate model EC-Earth. Nudging sea ice only in the Barents-Kara Seas, five configurations of sea ice covers are used to assess the importance of the amount of sea ice in this region. Nudging in the coupled model is achieved by modifying the non-solar surface heat flux into the ice/ocean interface. The mean winter temperature response suggests a weak but statistically significant non-linear response with cooling over eastern Europe for moderate sea ice reductions in the Barents-Kara Seas, a weaker but still cold anomaly for minor reductions and warming for major reductions. However, this non-linear response is not reflected in the circulation. Instead, a negative mean sea level pressure anomaly over Barents-Kara Seas intensifies with sea ice reduction. In contrast to this, is the response in the coldest winters over central Europe: the larger the sea ice reduction, the stronger the Scandinavian pattern and the associated easterlies need to be to obtain cold winters over central Europe. The use of a coupled climate model is a potential explanation for the link between the intensified Scandinavian pattern and the cooling over Europe seen in this study, that is not observed in some atmosphere-only model studies.
A link between reduced Barents‐Kara sea ice and cold winter extremes over northern continents
Published 5 Nov 2010
The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, as for example, extremely cold winter 2005–2006 in Europe and northern Asia. Here we show that anomalous decrease of wintertime sea ice concentration in the Barents‐Kara (B‐K) seas could bring about extreme cold events like winter 2005–2006. Our simulations with the ECHAM5 general circulation model demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it, being in qualitative agreement with the simulated large‐scale atmospheric circulation realignment. Furthermore, our results suggest that high‐latitude atmospheric circulation response to the B‐K sea ice decrease is highly nonlinear and characterized by transition from anomalous cyclonic circulation to anticyclonic one and then back again to cyclonic type of circulation as the B‐K sea ice concentration gradually reduces from 100% to ice free conditions. We present a conceptual model that may explain the nonlinear local atmospheric response in the B‐K seas region by counter play between convection over the surface heat source and baroclinic effect due to modified temperature gradients in the vicinity of the heating area.