Early onset of significant local warming in low latitude countries

By Irina Mahlstein, Reto Knutti, S. Solomon, R. Portmann. 2011

292 citations recorded by the source corpus.

The Earth is warming on average, and most of the global warming of the past half-century can very likely be attributed to human influence. But the climate in particular locations is much more variable, raising the question of where and when local changes could become perceptible enough to be obvious to people in the form of local warming that exceeds interannual variability; indeed only a few studies have addressed the significance of local signals relative to variability. It is well known that the largest total warming is expected to occur in high latitudes, but high latitudes are also subject to the largest variability, delaying the emergence of significant changes there. Here we show that due to the small temperature variability from one year to another, the earliest emergence of significant warming occurs in the summer season in low latitude countries (≈25°S–25°N). We also show that a local warming signal that exceeds past variability is emerging at present, or will likely emerge in the next two decades, in many tropical countries. Further, for most countries worldwide, a mean global warming of 1 °C is sufficient for a significant temperature change, which is less than the total warming projected for any economically plausible emission scenario. The most strongly affected countries emit small amounts of CO2 per capita and have therefore contributed little to the changes in climate that they are beginning to experience.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/c37d884579a184d1cde7fec681528cfb72fa146e

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Citations in the corpus

Explaining Extreme Events of 2015 from a Climate Perspective (2016, result): “Our results are in line with time of emergence studies in that regard (e.g. King et al. 2015; Mahlstein et al. 2011), which find an earlier warming signal in tropical regions such as Indonesia due to a high signal-to-noise ratio.”
The timing of anthropogenic emergence in simulated climate extremes (2015, background): “Previously, efforts to calculate time of emergence have focused on mean temperature and precipitation (Giorgi and Bi 2009, Mahlstein et al 2011, 2012a, 2012b, Hawkins and Sutton 2012) and recently, sea level rise (Lyu et al 2014).”
Partitioning climate projection uncertainty with multiple large ensembles and CMIP5/6 (2020, background): “Scenario uncertainty increases earliest in the tropics, where signal to noise is known to be large for temperature (HS09; Mahlstein et al., 2011; Hawkins et al., 2020).”
The Inequality of Climate Change From 1.5 to 2°C of Global Warming (2018, background): “Similar results have been found previously (Hawkins & Sutton, 2012; King et al., 2015; Mahlstein et al., 2011, 2012; Schleussner et al., 2016), but it is remarkable that this difference in S/N ratios is so apparent for only a 0.5°C difference in global temperature.”
Poorest countries experience earlier anthropogenic emergence of daily temperature extremes (2016, background): “…populate lower latitude regions, where the low variability in temperature enhances the pace of emergence of a given signal-tonoise ratio when compared with higher latitude regions (Hawkins and Sutton 2009, Diffenbaugh and Scherer 2011,Mahlstein et al 2011, Hawkins et al 2014, Hansen and Sato 2016).”
Global crop exposure to critical high temperatures in the reproductive period: historical trends and future projections (2013, background): “However, given low inter-annual variability and currently high temperatures in the tropics, warming signals may be more noticeable and have greater impacts in these locations [40].”
Modelling sea level rise impacts on storm surges along US coasts (2012, result): “Our general finding echoes a recent result from Mahlstein et al (2011), who found that local temperatures will depart from historical ranges faster in the tropics than in high latitudes, because lower tropical temperature variability will outweigh the slower warming there.”