A Victory For 2014

As 2014 draws to a close it is important to look at arguably the greatest victory of the year for climate change... of course i'm referring to the United States and China coming together to form an agreement on tackling climate change! In case you missed it, the story is summed up quite nicely by the following news report from CNN...

"As the world's two largest economies, energy consumers and emitters of greenhouse gases, we have a special responsibility to lead the global effort against climate change" -(well duh!) Barack Obama, 2014 

The historic deal was signed November 12th and some of the main points include:

• America to double the speed of their current pollution reduction trajectory
• America's new aim is to reduce greenhouse gas emissions 28% below 2005 levels by 2025
• US and China will continue to work together on the CO2 capture and storage technology that will help clean up coal burning for power plants, this will be achieved through increasing funds to the U.S.-China Clean Energy Research Centre
• China hopes to peak CO2 emissions and increase the use of non fossil fuel energy to 20% by 2030 (Biello, 2014)

The agreement and progress made through this agreement hopefully means that the US and China will get involved in the UN's Framework Convention on Climate Change in Paris next year, and sign an agreement with the rest of the world's leaders. It would be the first time either nation has committed on paper to reducing emissions. Very promising stuff for 2015!

The Need For Change: Fire!

There have been two major forest fires in Northern America in 2014, a light relief compared to the five major forest fires of 2013 and the seven of 2012. The first in 2014 was in Washington and within four days of the fire starting 300 homes had been destroyed, the second was in British Columbia and was the largest in British Columbia since 1982 and destroyed over 300,000 acres of land. This is obviously a problem. Forest fires are a big problem when they have the ability to destroy so much land and harm so many people and the effect of changing climate on forest fires is something that needs to be considered.

Forest Fire, Bitterroot National Forest, USA. 2000.
Source: Reddit

Wildfires have a large range of contributing factors including temperature, humidity, wind and the location of lightening strikes. However human factors such as fuel and land management can contribute to wildfires too. (Westerling, 2003) The atmospheric conditions conductive for wild fires are expected to change with climate change - thus the patterns and frequency of wildfires are also subject to change. But how?

A recent study by Tang et al to be published early January next year has looked into the effects of climate change on the atmospheric conditions that are associated with wildfires. They've done this using simulations from multiple regional climate models and used a comparison between the current climate and the predicted climate of 2050 to look at the differences. To compare the atmospheric conditions Tang et al have used the Haines Index.

Definition: Haines Index - "a measure of how conductive the atmosphere is to potential extreme or erratic fire behaviour based on atmospheric stability and moisture" (Haines, 1988) hence can be split into two parts a humidity component and a stability component. A value of 5 or 6 on the index signals a high level of potential for wildfires. (Tang, 2015)

The models show that by 2050 there is relatively little change in spatial and seasonal patterns - meaning regions for erratic wildfires at present will remain regions for erratic wildfires in the future. Key regions have been highlighted by the paper such as Intermountain West, High Plains and the Gulf Coast region, hopefully the results of the simulations will have some influence over future land use planning in these high risk areas to help accommodate with the upcoming climate change. The models also identified an increase in the percentage of days with a high HI index and also an increase in duration of successive days with high HI indexes. (Tang, 2015) These increases in HI index are representative of an increased risk of wildfires, meaning with increased climate change there can be expected higher chance of wildfires. Hence providing mounting evidence for the detrimental effect of climate change in the US and the need for a big change!

Source: Giphy

A Christmas Guide

Funnily enough I found out that one of my flatmates, a third year UCL biologist and also a proud Canadian, doesn't believe in global warming. She believes it's happening but the idea that humans are behind it she shot down and just flat out doesn't believe. She's a scientists though, how can't she see the evidence? She doesn't believe it and there's no amount of arguing my friends and I can do to convince her, we're simply avoiding the subject for the rest of our tenancy.

Here's a fun, quick guide to help you all deal with climate change deniers over the holidays...

Hope it helps!

Source: Giphy

Tipping Elements

Previously discussed was the idea of tipping points – it was briefly mentioned the idea of tipping elements however I did not elaborate on this.  So briefly I will look into some of the most important tipping elements now to give you an idea of where they can be found! I will explain why each one may be a potential tipping element and its importance in the earth’s system.

Arctic Sea-Ice: simply, as sea ice melts a darker ocean surface is exposed so more radiation can be absorbed. This amplifies warming! This provides a positive feedback system on climate. (Lenton, 2008) Data shows that both summer and winter sea ice are declining at present, with large areas showing a great deal of thinning. (Stroeve, 2007) Is there a cut off point for the melting of sea-ice that will be the tipping point?!

Source: NASA
The 2010 shot of the Arctic Sea Ice. This year showed a maximum in sea ice that was unexpected from the trend of the previous years, however was still below the 30 year average. (NASA, 2010)

Greenland Ice Sheet: warming of the ice sheet at its periphery lowers the altitude of the ice and as a result increases the surface temperature. Again this leads to positive feedback, in addition there is potential that this could cause the ice sheet to disappear. (Lenton, 2008) The IPCC (2007) have put this threshold for the disappearance of the ice sheet between 1.9°C-4.6°C above pre-industrial levels – one we can all agree isn’t too far off the horizon…

Atlantic Thermohaline Circulation (THC): The THC plays a large role in the rapid climate changes that have been recorded in Greenland in its historic records.  Should a large amount of water or heat enter the North Atlantic, the North Atlantic Deep Water formation and the connected Atlantic THC will be caused to shut off. All models of this have so far showed a collapse of convection and a tipping point being crossed, thus having a large effect on climate. (Lenton, 2008) The IPCC (2007) claim this is unlikely to occur anytime before 2100 (not long in the grand scheme of things) and that any subsequent transition would take more than a century. (so maybe let’s not worry too much about this, who knows?)

It is the uncertainty in the tipping points that make them more worrying. However with increased research several tipping elements have been identified and the warning signs for approaching tipping points are becoming somewhat better understood. This does not make them any more promising for the future of the earth’s climate, there is still a quite desperate need to avoid them!

The Need For Change: Tipping Points

The United States is the second biggest contributor to greenhouse gas emissions; making it, by default, the second biggest contributor to global warming. But why should this matter and why should they change their ways?

Truth be told, there is a great deal of uncertainty regarding climate change but something that is really worrying scientists is the idea of tipping points.

A tipping point is defined as a small change in forcing triggers that results in a nonlinear response in the dynamics of the climate system. These forcing triggers are defined as tipping elements and candiates for these include:
-melting of Greenland ice sheet
-dieback of the Amazon rainforest
-the shift of the West African monsoon
Recently, there has been research carried out into these tipping elements to strongly suggest an increased probablity of their occurance. Changing tipping points from a "high-impact low-probability" event to possibly "high-impact high-probability" events. (Lenton, 2011)

The melting of the Greenland Icesheet: Irreversible
A Tipping Element
Source: FFFound

Warning Signs

These events can manifest several early warning signs ranging from simply the knowledge that it could occur, through to predictions of the timings of events. The study of these warning signs have been carried out through the study of past events. These past events are characteristic of sharp climatic transitions from one state to another. For example 34 million years ago, the greenhouse-ice transition that showed the change in the earths climate from tropical to a state with ice-caps; to the 5000 year ago that showed a sudden climatic shift in Africa from a savanna-like climate to one of desert. The suggested explanatons for these climatic shifts studied have usually invoked the idea of a tipping point. (Dakos, 2008)

Through the study of these past shifts that have been thought to include tipping points it has providing climate scientists with indications of warning signs for these events. One of the prominent warning signs has been seen in the 'slwoing' of dynamic systems before a tipping point. The theoretical data given shows that "dynamical systems become 'slow' when a critical point is approached as conditions are gradually changing". (Dakos, 2008) For the scope of this blog and for the sake of my sanity, so I don't try and tackle with quantum physics, it can be concluded that dynamic systems become increasingly slow in their recovery from small peturbations. Despite research into this area, the restictions of climate models has meant there has yet to be any significant studies of slowing down before a shift in real data. However the Dakos paper did found significant evidence for this slowing down on modeled data from past climate shifts.

This general idea is one called bifurcations and it is the slow forcing past a bifurcation point that is analogous to that of a tipping point. This theory provides the greatest promise for an early warning indicator. The idea of slowing down in dynamic systems is one that has been around for a great deal of time but only recently been applied to climatic problems. (Lenton, 2011) The prcoess of bifurcation can be understood in then visualisation below. The circles represent the state of the climate and how it's repsonse to perbutations changes with proximaty to the bifurcation (tipping point). The final graph shows that with the state of the climate at a tipping point the response is to slip into a different state rather than recover.

A representation of bifurcation - Lenton, 2011

Warning systems are in place for several natural hazards already such a tsunamis and hurricanes, stressing the importance of these warning signs for tipping points. The UN has called for a comprehensive, globally integrated early warning system for all natural hazards and tipping points should definitely be included in this as the effects of crossing a tipping point will have serious implications on the human race and the earth system.