How much have temperatures risen already? As illustrated by above image, NASA data show that during the three-month period from September through November 2015, it was ~1°C warmer than it was in 1951-1980 (i.e the baseline).
A polynomial trend based on the data from 1880 to 2015 for these three months indicates that a temperature rise of 1.5°C compared to the baseline will be reached in the year 2024.
Let's go over the calculations. The trendline shows it was ~0.3°C colder in 1900 compared to the baseline. Together with the current ~1°C rise, that implies that since 1900 there's been a rise of 1.3°C compared to the baseline. This makes that another rise of 0.2°C by 2024, as pointed at by the trendline, would result in a joint rise in 2024 of 1.5°C compared to the baseline.
The situation is even more worse than this. The Paris Agreement seeks to avoid a temperature increase of 1.5°C above pre-industrial levels. When we include temperature rises from pre-industrial levels to the year 1900, it becomes evident that we have already surpassed a rise of 1.5°C since pre-industrial levels. This is illustrated by above image, earlier added at How much time is there left to act? (see notes there) and by the graph below, from a recent post by Michael Mann, who adds that ~0.3°C greenhouse warming had already taken place by the year 1900.
|~0.3C greenhouse warming had already taken place by 1900, and ~0.2C warming by 1870|
In other words, we have already surpassed a rise of 1.5°C from pre-industrial levels by 0.1°C.
The trendline indicates that a further rise of 0.5°C will take place by the year 2030, i.e. that without comprehensive and effective action, it will be 2°C warmer than pre-industrial levels before the year 2030.
Full wrath of emissions yet to come
The full wrath of global warming is yet to come and the situation is even more threatening than pictured above, for the following reasons:
- Half of global warming has until now been masked by aerosols, particularly sulfates that are emitted when some of the dirtiest fossil fuels are burnt, such as coal and bunker oil. As we make the necessary shift to clean energy, the masking effect that comes with those emissions will disappear.
- As Ricke and Caldeira point out, the carbon dioxide that is released now will only reach its peak impact a decade from now. In other words, we are yet to experience the full wrath of the carbon dioxide emitted over the past decade.
The image on the right illustrates this with a forecast for December 25, 2015, showing extreme weather for North America, with temperatures as low as 30.6°F or -0.8°C in California and as high as 71.5°F or 22°C in North Carolina.
- Feedbacks such as rapid albedo changes in the Arctic and large amounts of methane abruptly released from the Arctic Ocean seafloor could dramatically accelerate the temperature rise. Furthermore, water vapor will increase by 7% for every 1°C warming. Water vapor is one of the strongest greenhouse gases, so increasing water vapor will further contribute to a non-linear temperature rise. The resulting temperature rises threaten to be non-linear, as discussed in the final section of this post.
Such temperature rises will hit some people more than others. For people living on the Northern Hemisphere, the outlook is worse than for people on the Southern Hemisphere.
NOAA data show that the November global land and ocean temperature anomaly was 0.97°C, while the 3-month global land and ocean temperature anomaly was 0.96°C. The 12-month anomaly on November 2015 on land on the Northern Hemisphere (where most people live) was 1.39°C, as shown on the image below, while the trendline shows that for people living on the Northern Hemisphere, a 1.5°C rise compared to 1910-2000 could be reached as early as in 2017.
Similarly, the outlook is worse for people living in regions that are already now experiencing high temperatures during the summer peaks. As said, as temperatures rise, the intensity of such peaks will increase.
Feedbacks in the Arctic
The image below, from an earlier post, depicts the impact of feedbacks that are accelerating warming in the Arctic, based on NASA data up to November 2013, and their threat to cause runaway global warming. As the image shows, temperatures in the Arctic are rising faster than elsewhere in the world, but global warming threatens to catch up as feedbacks start to kick in more. The situation obviously has deteriorated further since this image was created in November 2013.
|[ click on image at original post to enlarge ]|
The image below shows sea surface temperature anomalies on the Northern Hemisphere in November.
The image below gives an indication of the high temperatures of the water beneath the sea surface. Anomalies as high as 10.3°C or 18.5°F were recorded off the east coast of North America (green circle on the left panel of the image below) on December 11, 2015, while on December 20, 2015, temperatures as high as 10.7°C or 51.3°F were recorded near Svalbard (green circle on the right panel of the image below), an anomaly of 9.3°C or 16.7°F.
This warm water is carried by the Gulf Stream into the Arctic Ocean, threatening to unleash huge amounts of methane from its seafloor. The image below illustrates the danger, showing huge amounts of methane over the Arctic Ocean on December 10, 2015.
Methane is released over the Arctic Ocean in large amounts, and this methane is moving toward the equator as it reaches high altitudes. The image below illustrates how methane is accumulating at higher altitudes.
Above image shows that methane is especially prominent at higher altitudes recently, having pushed up methane levels by an estimate average of 9 ppb or some 0.5%. Annual emissions from hydrates were estimated to amount to 99 Tg annually in a 2014 post (image below).
An additional 0.5% of methane represents an amount of some 25 Tg of methane. This comes on top of the 99 Tg of methane estimated in 2014 to be released from hydrates annually.
The situation is dire and calls for comprehensive and effective action as described at the Climate Plan.
• How Close Are We to 'Dangerous' Planetary Warming? By Michael Mann, December 24, 2015
• Maximum warming occurs about one decade after a carbon dioxide emission, by Katharine L Ricke and Ken Caldeira (2014)
• How much time is there left to act?
• Feedbacks in the Arctic
• Climate Plan