Not hard to see how 2018, an El Nino year, ended up fourth hottest year. You can see it started out below recent years in Jan & Feb but a couple months later it warmed up. We know why: Australia had a warm spring and winter (with some anomalous low readings due to frost in drought struck areas NSW-Qld) and the NH had a very hot summer.
2019 was slated to be an El Nino year but some cold water changed that. BoM still predicts:
El Niño WATCH for autumn
The El Niño–Southern Oscillation (ENSO) is currently neutral. However, the Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is approximately a 50% chance of El Niño developing during the southern hemisphere autumn or winter.
http://www.bom.gov.au/climate/enso/So far 2019 has record heat in Australia and South America with 30°C readings further south than previously recorded. Parts of the US and Europe have very low temperatures due to an affect called “Polar Vortex” which ultimately has to do with AGW and Arctic Amplification of it: what happens in the Arctic need not stay in the Arctic anymore. Arctic ice so far is higher in extent than 2018, just below the 2012 record low extent. Extent is only one part of the picture, we need to know ice volume or thickness to see how Arctic ice is going.
I had expected a winter melt but one has not happened. Probably will winter 2019/20 because these events have been happening more frequently this century including back to back 2016/7 and 2017/8 winter melts.
2018 was a La Nina year and La Nina’s bring cooler weather. Yet 2018 was warmer than huge El Nino year 1998! Global warming is real. What is causing AGW (and consequent sea level rise) needs to be considered:
1. Is it due to chance, just internal variability? Nope, warming been going on nearly all 20th and 21st centuries.
2. Is it due to coming out of the Little Ice Age? No, that was not a real ice age and temperatures only dropped 0.5°C from the Medieval Warm Period that preceded it. We are warmer now than the Medieval and the preceding Roman Warm Periods—again, unlikely just random variation over 100 years. 1°C warming is huge, takes energy to warm the whole atmosphere and seas down to 2000 metres!
3. Is it the sun? Deniers of AGW always claim the sun drives climate. No, over the long term, of a century say, the suns output is too steady to cause climate change. Over geologic time the sun gets brighter. Since the Ediacaran and Cambrian (600 million years ago) the sun has brightened by 4% so very general increase in solar output matched by a decrease in CO2 keeping temperatures reasonably stable over geologic time. So not the sun: the sun in the 1960s and again in the 1980s decreased output slightly.
4. Other factors are driving the warming, particularly CO2 emitted by man. CO2 emitted by volcanoes is about 1% the amount we emit annually. This can be summarised neatly:
[img]Not hard to see how 2018, an El Nino year, ended up fourth hottest year. You can see it started out below recent years in Jan & Feb but a couple months later it warmed up. We know why: Australia had a warm spring and winter (with some anomalous low readings due to frost in drought struck areas NSW-Qld) and the NH had a very hot summer.
2019 was slated to be an El Nino year but some cold water changed that. BoM still predicts:
El Niño WATCH for autumn
The El Niño–Southern Oscillation (ENSO) is currently neutral. However, the Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is approximately a 50% chance of El Niño developing during the southern hemisphere autumn or winter.
http://www.bom.gov.au/climate/enso/So far 2019 has record heat in Australia and South America with 30°C readings further south than previously recorded. Parts of the US and Europe have very low temperatures due to an affect called “Polar Vortex” which ultimately has to do with AGW and Arctic Amplification of it: what happens in the Arctic need not stay in the Arctic anymore. Arctic ice so far is higher in extent than 2018, just below the 2012 record low extent. Extent is only one part of the picture, we need to know ice volume or thickness to see how Arctic ice is going.
I had expected a winter melt but one has not happened. Probably will winter 2019/20 because these events have been happening more frequently this century including back to back 2016/7 and 2017/8 winter melts.
2018 was a La Nina year and La Nina’s bring cooler weather. Yet 2018 was warmer than huge El Nino year 1998! Global warming is real. What is causing AGW (and consequent sea level rise) needs to be considered:
1. Is it due to chance, just internal variability? Nope, warming been going on nearly all 20th and 21st centuries.
2. Is it due to coming out of the Little Ice Age? No, that was not a real ice age and temperatures only dropped 0.5°C from the Medieval Warm Period that preceded it. We are warmer now than the Medieval and the preceding Roman Warm Periods—again, unlikely just random variation over 100 years. 1°C warming is huge, takes energy to warm the whole atmosphere and seas down to 2000 metres!
3. Is it the sun? Deniers of AGW always claim the sun drives climate. No, over the long term, of a century say, the suns output is too steady to cause climate change. Over geologic time the sun gets brighter. Since the Ediacaran and Cambrian (600 million years ago) the sun has brightened by 4% so very general increase in solar output matched by a decrease in CO2 keeping temperatures reasonably stable over geologic time. So not the sun: the sun in the 1960s and again in the 1980s decreased output slightly.
4. Other factors are driving the warming, particularly CO2 emitted by man. CO2 emitted by volcanoes is about 1% the amount we emit annually. This can be summarised neatly:
