Measuring Earths Climate - Modern Day Methods

So as I’m sure a lot of you have seen there are estimates on how the Earth’s climate has changed for many thousands of years. All of them are suggesting that we are currently experiencing an upward trend which isn’t great news but that is not what this post is going to be focusing on. Humans have only really been measuring temperatures for the last few hundred years, so the question is where did these reading come from?

Well there are so many different methods of measurin

g climate that I’m going to do split it into a couple of different posts.

To start with we are going to look into the current methods of measuring temperature in really time. Now in most cases this means that an item known as a Stevenson shelter is used. It is possible that you’ve even seen one of these, possibly out the window while waiting at an airport. A Stevenson shelter is a standardised white box which lifts a thermometer away from the heat being radiated from the ground whilst being well shaded and receiving a good amount of air flow across a standard thermometer.  There are problems with Stevenson shelters however, for instance until recently very few of these boxes were found in the southern hemisphere, this has leads to historic data being unevenly distributed across the global. Another issue is the physical location of each shelter, as to get reliable long term data ideally shelters should remain in the same spot. Unfortunately increased urbanisation creating both heat island and the need for space has meant that a lot of shelters are being moved which can also disrupt data.

It’s not only air temperature which records are kept on, sea surface temperatures have also been monitored for several hundred years, but the methods of doing so have been changing. At first a wooden bucket was lowered of the side of a ship and the temperature was gained from this small sample. This wooden bucket was then replaced with a canvas bucket in the late 19^th century which caused a spike in temperatures due to the insulating properties of canvas and wood. This practise was again changed during World War 2 as the water sample was taken from the engine inlet valve instead of the side of the ship so again a second jump in temperature readings was seen. The lack of consistencies within the measuring protocol has meant they require a standardisation so as a consistent record can be created. There are also further problems with measuring sea surface temperature which are similar to Stevenson shelters in the fact that in the beginning ships were usually confined closer to shore the majority of the time, so overall coverage of readings are at points an issue. In recent years a modern method for monitoring sea surface temperature has been developed which uses satellite imaging to provide nearly complete coverage sea across the world. Yet again these measurements need to be standardised to continue temperature records. These satellites can also be used to measure sea level rises.

The final modern method of measuring deep water temperatures are Agro floats. These are autonomous robots which are capable of descending two thousand meters under the oceans and taking multiple different temperatures reading over the course of ten days before it resurfaces and uploads the data to a series of satellites. These floats are important as changes in deep sea temperatures could seriously disrupt their productivity and so have a knock on effect on shallower waters and terrestrial environments. However like ever kind of measurements there are limitations, for instances there have been problems with the floats becoming trapped under ice when taking reading close to the poles and so the spread of data is disrupted again.

So these are just a few modern methods which are utilised to measure

the changes in the Earth’s climate to allow us to see how human activities and natural variations are effecting global temperatures. However as I said earlier this is just the tip of the iceberg, we currently have accurate global temperature records for many thousands of year so how was these achieved?

The answer is through the use of proxy measurements.

Stay tuned for the second of these two  posts which will look into exactly how proxy measurements are used in historical records.

Thanks for reading!

Check out this link which shows a remarkable amount of progress in the UK when it comes to shopping bags.

http://www.bbc.co.uk/news/science-environment-36917174

Check out this video from Redbull

Weekly Article - We Can Make A Difference

Although this article was published a few days ago but I still think that it is important that you see this if you haven't already.

Recently India came together as a country with 800,000 volunteers to do some good for the world. They successfully planted 49.3 million saplings in a grand total of 24 hours. This is a truly staggering amount of trees and was actually done as an attempt to break the world record which was previously held by Pakistan. However although this is defiantly a step or even a jump in the right direction it only equates to just under the number of trees which were cut down in just 20 days in 2014 (that's 900 million annually) so sadly we can't jump to the conclusion that we've halted deforestation.

Check out the links below to see a few different

http://news.nationalgeographic.com/2016/07/india-plants-50-million-trees-uttar-pradesh-reforestation/

http://www.sciencealert.com/india-planted-50-million-trees-in-just-24-hours-last-week

hopefully this has made your day a little bit brighter

Thanks for reading!

Marine Iguanas - A Lizard On Its Own

So this post follows on from the article which was posted on Wednesday, which concerned the idea that islands cause the evolution of weird and wonderful animals, due to their isolation and other contributing factors.

The animal which we will be looking at in this post is the Marine Iguana or Amblyrhynchus cristatus, which can only be found on the Galapagos Islands. This species is unique among modern lizards and one of only a handful of reptiles which take to the sea to feed. Clearly being a reptile is problematic for a marine existence as the cold sea water will slowly leaches an iguanas heat from its body and being ectothermic an Iguana is unable to replace this lost heat. The iguanas are able to overcome this however by spending a lot of time bathing in the sun and thanks to their colouration they are capable of quickly absorbing heat. Along with this iguanas are usually found along rocky areas of the coastline, this allows them to gain maximum exposure to the sun whilst out of the water, along with being able to absorb heat radiating from the rocks they sit on.

However when an iguanas body temperature does drop it will like all reptiles become slower and react sluggishly to stimuli such as the presence of a predator. Therefore iguanas have evolved a behaviour to deal with this issue, when threatened a cold individual will display high levels of aggression in an attempt to postpone potential attacks and create an escape route. However even with these behavioural responses Marine Iguanas are still in decline as introduced species such as cats, rats and dogs have been seen to prey upon them and so as of 2004 Marine Iguanas are rated as vulnerable on the IUCN red list. Also due to the fact a survey on population size has not been carried out for 12 years and the known negative effect of climatic phenomenom such as El Nino have on marine Iguanas means that potentially there are currently fewer Marine Iguanas than is believed.

Events such as El Nino have a negative effect on population numbers (up to 85% mortality rates) due to a number of reasons. For instance the event in 1982-83 caused high rainfall which flooded nests, increased sea levels which meant that a higher proportion of their food source was found at a depth iguanas could not achieve and finally increased surface temperatures which reduced the marine productivity of the area and so reduced food sources yet further.

Marine Iguanas feed primarily on 4-5 different red algae species along with a less favourable but more common green algae species with the regional feeding zones being dictated by the size of an individual. Smaller individuals tend to feed in the intertidal ranges where food is easily available and diving is not needed, while larger individuals feed further out. Dives are typically to depth of 1.5-5m but large adults have been seen to go to depths of up to 3 times this.

Throughout their time spent feeding Iguanas are constantly absorb excess salt from the water. To deal with this issue these iguanas have evolved special nasal glands which allow them to excrete the excess salt from there system with a method which looks like they are sneezing. This is extremely beneficial for iguanas as if the excess salt had to be passed out through their urine they would require vast quantise of water to allow them to perform such a process.

So overall Marine Iguanas are a perfect example of how island ecology gives rise to creates you would never see in mainland populations.

There is a tonne of other resources out there on the web for anyone who wants to find out some more on these amazing animals, but I’ve linked two good sites just to get you started.

http://www.arkive.org/galapagos-marine-iguana/amblyrhynchus-cristatus/

http://www.iucnredlist.org/details/1086/0

Thanks for reading!

Check out these videos!