The Dutch ambassador isn’t worried:

Dutch ambassador Wim Geerts, who grew up with tulips, said Ottawa residents shouldn’t worry as things could change between now and festival time. "We’ll keep our fingers crossed," he said.

The organisers of the tulip festival plant the tulips to bloom in the early, middle or late season. They planted more than a million bulbs in October 2009.

There is no option of rescheduling the festival to coincide with the blooming of the tulips. "It’s a force that can’t be stopped," said Christine Charette, the festival’s director of planning and operations. "We have booked many acts. It has to begin as scheduled."

The festival, which runs from May 7 to May 24, draws close to 600,000 visitors to the Ottawa area.

Charette says she is hopeful. "This is Canada. It could snow tomorrow. We’re not too worried."

Source: Ottawa Citizen

It’s a good question. Throughout the history of life on Earth, species have shifted where they live in response to changing environmental conditions. Abrupt changes in climate and the environment  can outpace the speed at which plants can adapt. The consequence is local extinction.

The fossil record provides an indication of the rate at which plants can migrate:

• 0.04 km/yr for the slowest species
• 2 km/yr for the fastest species

Projected rates of temperature change, and therefore environmental change, exceed the migration speeds of many plant species, requiring migration rates of 1.5 to 5.5 km/yr. Many plant species will simply not be able to keep up, and ecosystems are going to see a lot of changes.

The future, therefore, looks weedy. Mobile, opportunistic and climatically tolerant species will do well in this unstable, fast changing world.

Resources

1. Estimated migration rates under scenarios of global climate change. Malcom et al, 2002. [Link]
2. Why can’t ecosystems just adapt? [Link]

The alpine and tundra wildflower Dryas octopetala has the honour of lending its name to a period of climate change called the Younger Dryas, around 10,000 years ago, when glacial conditions rapidly set in across the higher Northern Hemisphere. Pollen from the Dryas flower suddenly began to appear in ice cores. The abrupt arrival of the alpine flower in the record signalled a dramatic change in climate.

The idea that climate could change abruptly challenged the gradualistic world view of the time. Now, the prevailing theory for the cause of the Younger Dryas is that a sudden influx of water from North America shut down the thermohaline circulation.

How will our present epoch be defined? The world is currently entering a period where human influences on our environment will leave clear and discernible fingerprints in the geological record. The pollen record will tell of cultivated plants, wheat and cereal crops, all the tell-tale spore of humanity, of agriculture replacing native plants.

What about uncultivated plant species? In the pollen record, imported plants, exotics and escapees would appear as sudden spikes in sites all over the world. Pollen dispersal, previously restricted by geography, that has been facilitated by human activity.

The world still has its uninhabitable regions, where the vegetation has not been directly altered by human influence. Nonetheless it too will show the signature of the Anthropocene.

The climate is changing once again, but this time Dryas octopetala is not moving South, leafing down from its northern latitudes. However, the taiga is moving north. As the treeline migrates into the tundra, as the tundra retreats and the permafrost melts, our epoch may come to be defined not by the abundance of Dryas, but by its absence.

"The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time." [NASA]

Discussing weather events in the context of climate change isn’t simple. To be correct, we need to state that ‘on average’, the weather may be different. If an unusual weather event occurs, that one event can’t be attributed to climate change, but we can expect more such events over time.

One way in which humans can observe climate change on a personal level is taking notice of earlier flowering dates. The arrival of crocuses in the northern hemisphere is an eye-catching event. We notice it and see it as portending the end of winter, and  may notice it happening earlier and earlier each year.

The study of the times of recurring natural phenomena is called ‘phenology‘. 

For a tree to produce flower buds, open and flower, a succession of events must take place. It begins with a rise in the air temperature. This allows the vapour pressure at the leaf surfaces to reach a point for transpiration to occur. Sap begins to rise. Leaves require sunlight and a stable range of temperature; once leaves are set, a cold snap can kill them. Leaves on an tree can be taken, to anthropomorphise, as a sign of optimism and expectation that the long term weather will be favourable. The rising sap and water from the roots move sugars and starch around the tree. Sinks of sugars build up in the flower sites. When all these events have occurred in succession, flower development can begin. In the cherry tree, it is spectacular. Flowers grow, pollen forms, insects are drawn to the nectar and take the pollen with them to receptive flowers. These insects themselves need their own favourable chain of circumstance, and all these links in these chains are susceptible to the weather.

Long term, cold temperatures will delay the beginnings of the process. Brief, unusual warm periods in the winter can trigger the start of growth at too early a date.

Trees are an example of a very long term response. The amount of sunlight in the preceding year will affect the amount of fruit set in the next year. Plants respond in the short term to cold or hot snaps, of a day or a week, but when they flower, the average dates when crocuses emerge from the soil, when cherry trees bloom: these events are a response to the climate. If spring comes early, the chain begins early. Plants, in their lifecycles, integrate all the events that happen to them. Their fruit set or grain yield is the sum of the year of growth that preceded it. Plant growth is an averaging of weather, an integration of climate. When plants change their growth habits, take it as a sign that the climate has begun to change.

The Calvin Cycle is the most common method of carbon fixation.

In plants, there are three types of carbon fixation during photosynthesis:

C3 – a plant that uses the Calvin Cycle for the initial steps that incorporate CO2 into organic matter, forming a 3-carbon compound as the first stable intermediate. Most broadleaf plants and plants in the temperate zones are C3.

C4 – a plant that prefaces the Calvin Cycle with reactions that incorporate CO2 into 4-carbon compound. C4 plants have a distinctive leaf anatomy. This pathway is found mostly in hot regions with intense sunlight. Tropical grasses, such as sugar cane and maize are C4 plants, but there are many broadleaf plants that are C4.

CAM – plant that uses Crassulacean acid metabolism as an adaptation for arid conditions. CO2 entering the stomata during the night is converted into organic acids, which release CO2 for the Calvin Cycle during the day, when the stomate is closed. The jade plant (Crassula ovata) and Cactus species are typical of CAM plants.

{From wikipedia}